First Indian at the South Pole 3P.S. Sehra

Madame Marie Curie – Radioactivity and 10Atomic EnergyN.R. Dhar

Acharya Jagadish Chandra Bose – 19His Life and Work (1858-1937)D.S. Kothari

Assessment of Learning and 26Acquisition of Scientific TemperN. Panchapakesan

Conserving Biodiversity — 32An Important Environmental PriorityMonica Davar

Green Chemistry and Education 35Obote, Ime Bassey

Hearing – A Physical Phenomenon 39Vanitha Daniel and S. Suresh Kumar

Nanoscience and Nanotechnology: 43Perspectives and OverviewR. Ravichandran and P. Sasikala

An Investigation into Learning Difficulties 50Experienced by Indian Children inLearning Division Algorithm of Simple FactorsTapan Kumar Maiti and Jayant Kumar Maiti

On Composition of Natural Numbers 58M.N. Bapat and R.K. Sonwane

SCIENCE NEWS 61

BOOK REVIEW 77

SCHOOLSCIENCE

VOL. 44 NO. 2JUNE 2006QUARTERLY JOURNALOF SCIENCE EDUCATION

CONTENTS

First Indian at theSouth Pole*Sledge Odyssey to Antarctica

P.S. SEHRA

Professor of Meteorology AgronomyDepartment of Agricultural MeteorologyPunjab Agricultural UniversityLudhiana 141 004

DAPTABILITY certificate: Thinkingthat the Russian doctor on boardthe ship ‘Viese’ sailing to

Antarctica might be asking for myInternational Health Certificate, Ipromptly gave him that. But he smiledand remarked, “Wintering over the SouthPolar Ice-cap where the temperaturesrange from 40 to 90°C and the winds blowwith speeds exceeding 200-300 km perhour is not a joke, my friend. Yourcertificate is meant only for the poshcities of the world. Antarctica demandsfrom an individual the utmost inphysical stamina and mental soundnesswith mature judgement so that a manworking there may act quickly andpositively in order to survive. Prior toselection for Antarctica, we conduct athorough medical check-up and a toughphysiological and psychologicalscreening of our expedition members andalso impart them a special training. Onlyafter qualifying all these tests andtraining they are given ‘adaptabilitycertificate’ and taken to harshestcontinent Antarctica”.

Fig. 1: Icebergs floating in the frozen Antarctic Ocean

I did not undergo any specialacclimatisation programme or trainingbefore setting foot at the South Pole. I hadno ‘adaptability certificate’ and theSoviets (erstwhile USSR) allowed me toparticipate in their Antarctic Expeditionduring 1971-73 at my own personal risk.My long Antarctic ordeal included manyunforgettable scary moments in the ice.

What is Antarctica? In Greek itmeans “Anti-Arctic i.e. the opposite of theArctic”. Including its permanentlyattached ice shelves, Antarctica coversabout 5.5 million square miles(14.23×106km2 approximately) surro-unding the South Pole, and has 18,500miles (29,767km) of coastline. It is as bigas the United States and Mexicocombined. About 95 per cent of theworld’s permanent ice is in theAntarctic: 7 million cubic miles(30.5×106km3) of it. This great mass hasmade Antarctica the highest of allcontinents, its average elevation is about4,500 feet (225m). The world’s lowest

A

*Reproduced with permission from “Indian Mountaineer”, Vol. 2, 1978

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temperature minus 88.3°C has beenrecorded in Antarctica and violentsnowstorms with winds of over 250 kmper hour speed are very frequent in thisicy desert. It is the coldest and thewindiest continent.

Fig. 2: Map of Antarctica and South Pole

Although there is so much ice inAntarctica, there is almost no freshwater. Such a cold dry area cannotsupport much life of any kind. On landonly 4.5 per cent of which is bare, a fewprimitive plants exist, and there arebacteria and some insects and similarsmall animals. The Antarctic waters,however, abound in sea life ranging from

microscopic plants, plankton to giantwhales. The best-known birds inAntarctica are the flightless penguins,which walk erect and waddle along likea cartoonist’s version of man returningfrom a formal dinner! Wandering throughthe ice pack, penguins frequentlyencounter seals, six species of whichbreed in the Antarctic. There are alsocolonies of some flying birds such as thepolar skuas and snow petrels. To thepresent knowledge, Antarctica has neverhad any native human population. Mennow go to Antarctica primarily to studythe earth, the space around it and thelife upon it.

The climax of our AntarcticExpedition came in when we reached thegeographic South Pole. I got lost in mydeep thoughts while standing at thebottom of the world (90 degrees South)on a high ice-covered plateau more than9,000 feet (nearly 2,700m) above sealevel. The temperature at that time was60°C and the pressure much below thenormal. It was the place first reached bythe great Norwegian explorer RoaldAmundsen 60 years ago (1911). OnJanuary 17, 1912 about a month afterAmundsen, Captain Scott and four otherEnglishmen stood on the same spot, whowere later trapped by a blizzard andnever returned home.

At this historical place there is anAmerican station called Amundsen-ScottSouth Pole Station, which has been inoperation since 1957, the InternationalGeophysical Year. The sun sets here forthe winter on March 22, not to rise againuntil September 21. A full year consistsof only one day and one night, each ofsix months duration. On June 21, the

5FIRST INDIAN ATTHE SOUTH POLE

sun begins its ascent marking MidwinterDay. As at all stations this turning pointof the winter was celebrated with gusto.With the day marked by holiday routine,practically every one of us slept late. Theonly exception was our cook, who wasbusy preparing a lavish meal for thatevening.

Fig. 3: Glaciological and Geodetic observationsbeing made on way to Vostok. The authorparticipated in the 1,500 Km sledge odysseyfrom Mirny to Vostok, the pole of cold,completed in one and a half months

Now a desperate struggle of twomonths to reach ‘Vostok’, the pole ofinaccessibility and extreme cold (havingrecorded the world’s lowest temperature(minus 88.3°C). During our 1,500 kmtrekking from Mirny station to Vostoklocated at the geomagnetic South Pole,we had plenty of difficulties, wesometimes failed, we sometimes won, wealways faced them and made all possiblescientific observations.

Our trekking expedition comprisingof heavy machines ‘towmobiles’ and dogsledges carrying about 30 tons ofequipment for Vostok roared into actionand slowly pulled out of Mirny during thesummer. After two weeks, a heavysnowstorm began reducing the visibility

to zero. Most of the route was 3,000metres above sea level with constantlylow temperatures, about minus 70°C dueto which our snow tractors could notmove. Many of our huskies pulling oursledges died on the way and we had toeat their meat in order to survive.Snowstorms and poor visibility continuedto hinder our progress. One of ourcomrades who became ill with acuteappendicitis died on the way and yetanother fell into a deep crevasse andburied alive. Despite all these difficulties,we traversed 1,500 kilometres in twomonths, and conquered the pole ofinaccessibility. I can forget anything inmy life but not these tough experiences.I must add here that one who has nottravelled deep into the South Pole Ice-Cap cannot know Antarctica!

The coldest place in the world ‘Vostok’at 78.45 degrees South and 106.8degrees East lies at an altitude of 3,488*

metres on approximately 3,700 metres ofice. The air is perpetually drier then inthe world’s worst deserts. During thepolar night, temperatures drop so lowthat they would normally freeze carbondioxide out of the atmosphere whichcondenses at 78.5°C. The high altitudestarves lungs of oxygen, and the normalrate of heartbeats nearly doubles. Here15 of us wintered over, isolated fromcontact with rest of the world for morethan nine months, half of this time inutter darkness. I must say that sixmonths continuous darkness followed bysix months daylight at the South Polewere the extremely boring phenomena ofnature I experienced there. When Ireturned, I found that a 12 hour day

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followed by a 12 hour night were, indeeda great blessing!

During our 1500 km sledge odysseybetween Mirny and Vostak, we madesnow measuring observations and set upnew automatic stations for thecontinuous recording of magneticvariations and meteorological data inaddition to our other field work ongeodesy, glaciology and so on.

Circumnavigating all around theAntarctic continent on board theicebreaker ships ‘Navarin’ and ‘Ob’during the expedition, was most thrillingvoyage of my life which recalls me ofCaptain James Cook who between 1772to 1775 first sailed around Antarctic andbrought to an end the dream of aninhabited southern continent.

During the Antarctic circumnavi-gation our ships resupplied all theSoviet coastal stations viz. Mirny,

Leningradskaya, Bellingshausen,Novolazarevskaya, Amery andMolodezhnaya and relieved the old staffwith the new expedition members. Wesailed all along the Antarctic Circle andchose the site of a new Soviet station‘Russkaya’ on the shore of the Amundsensea. We took fuel and fresh foodprovisions for our ships and for theAntarctic stations from the port of PuntaArenas, Chile. But, unfortunately, thestation Molodezhnaya could not be givensufficient food supply due to which wehad to face a number of problems there.I visited several other stations operatedby the Antarctic Treaty member-nationsin order to collect maximum possiblescientific data.

Fig. 4: A view of the Soviet Antarctic station‘Molodezhnaya’. During the extremely cold,dark and stormy 6-month long night, some ofthe huts were blown off along with the inmates.Winters are harsh and there is plenty of snowaccumulation due to violent snow-storms.Some huts are built underground whereinsound does not reach, nor does light filterthrough.

Fig. 5: ‘M-100’ rocket at take-off from thelaunching-pad near ‘Molodezhnaya’ Antarcticstation during the extremely cold, dark andstormy 6-month long South Polar night

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return from there, misfortune followed myfootsteps. Growing weaker each day fromthe exertion and the lack of food, I alsoencountered violent storms and blizzardsand lost the way. I met with several hair-raising accidents during my South Poleodyssey, but fortune ever smiled on meand I always had a narrow escape.

In Antarctica, I was the ProjectScientist for carrying out the upperatmospheric rocket soundings from themain Soviet Station Molodezhnaya. TheM-100 rockets could carry 67 kg payloadupto 100 km altitude and were launchedtwice in a week. My research andinvestigations showed for the first time

that sizable perturbations occur in theSouth Polar atmospheric structureduring the winter.

My participation in the SovietAntarctic Expedition in 1971-73 wasmade possible (through the efforts of Prof.P.D. Bhavsar, Prof. P.R. Pisharoty and thelate Prof. Vikram A. Sarabhai) under anagreement between the Indian SpaceResearch Organisation and theHydrometeorological Service of the USSR.

Fig. 9: The author in the company of penguins.The penguins are very curious and social birdsand frequently come close to camps, ships andgroups of men to watch what is going on. Theyusually walk erect and waddle along lookinglike a cartoonist’s version of man returningfrom a formal dinner

Fig. 8: The seas surrounding the Antarcticcontinent freeze during winter months forhundred of miles offshore. In summer the icebreaks up to form pack-ice which constitutesa hazard to shipping and a barrier, makingaccess to the coast extremely difficult. Forthese reasons special ice-breaker ships are used

9FIRST INDIAN ATTHE SOUTH POLE

Editor’s Note

India is amongst few countries of the world that has been actively pursuingprogrammes to conduct wide ranging studies on Antarctica. It has alreadyestablished a permanent station on this icy continent. The first Indianexpedition to Antarctic Programme was undertaken in 1981. Since then Indiahas been sending multi-disciplinary scientific expeditions to Antarctica everyyear. In 1983 India commissioned its first research station in Antarctica,which was named as ‘Dakshin Gangotri’. It has since been replaced by theindigenously designed second Indian permanent station, ‘Maitri’ withadequate infrastructure facilities for conducting scientific research ofcontemporary nature in the icy continent. India has always recognised theimportance of preserving the pristine nature of this remote and uniquecontinent. To uphold this commitment, India, an original votary of the Protocolon Environmental Protection to the Antarctic Treaty, has ratified this Protocolin April 1996.

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A

Madame Marie Curie –Radioactivity and AtomicEnergy*

N.R. DHAR

Sheila Dhar Institute of Soil ScienceUniversity of Allahabad

S LATE as 1895 physicists andchemists seemed to be convincedthat the ultimate particles of

matter consist of atoms which cannot befurther broken down. In 1896, a newphenomenon, i.e., radioactivity, wasdiscovered by Henri Becquerel (1852-1908) of France, which changed ourideas regarding the ultimate particles ofmatter. The discovery of X-rays by Prof.Roentgen (1845-1923) in 1895, of cathoderays by J. Plucker (1801-1868) andothers also helped in modifying thescientists’ notion regarding the atom.

Prof. Becquerel was the Head of thePhysics Department of the NaturalHistory Museum in Paris and was anauthority on fluorescence of uraniumcompounds. He exposed a fluorescentpotassium uranyl sulphate crystal tosunlight and then placed it on aphotographic plate wrapped in blackpaper and observed an image of thecrystal on the photographic plate whenit was developed. In the next few daysthere was no sunlight in Paris andBecquerel put the crystal over aphotographic plate wrapped in blackpaper. In this case also an image of the

crystal appeared on the plate. Hereported to the French Academy ofSciences in February 1893 (Compt. rend.122, 420; 24 February, 1896) that thissalt, ‘must emit radiations which arecapable of passing through paper,opaque to ordinary light’. He alsoobserved that the same effect wasproduced in the dark and by otheruranium compounds, and the radiationsgiven out by uranium made a gasconduct X-rays and cathode rays. Thiswas the discovery of the radioactivity ofuranium, which is spontaneousdecomposition of matter into smallerparticles. This subject of radioactivitywas greatly advanced by Madame Curiewith the help of her husband, PierreCurie, because they made the capitaldiscovery that a very highly radioactivematerial, which was named radium, waspresent in the mineral pitchblende evenafter the removal of uranium compounds.Radium decomposes spontaneously andmuch more vigorously with liberation ofheat and other radiations than theuranium compounds. This discoverymade it possible for man to visualise theproduction of energy by the breaking ofatoms.

Marya (Marie) Curie was thedaughter of a Polish Professor Sklodovskaand was born at Warsaw on November7, 1867. As Poland was backward inscience at that time, she had to learnscience from books; but, in 1890 shecould carry on some elementaryexperiments in physics and chemistry inher cousin’s laboratory. She wanted tostudy science in the Great Centre of

* Reprinted from ‘School Science’, Vol. IV, No. 4, December, 1965.

11MADAME MARIE CURIE –RADIOACTIVITY AND ATOMIC ENERGY

Learning, Paris, and had to save moneyfor this purpose by serving as agoverness for about six years. She joinedfor a short while her sister and brother-in-law at Paris. Soon afterwards sheshifted to cheap lodgings and registeredherself for Licence Degree in ScienceFaculty, University of Paris, Sorbonne,in 1891. She obtained first position inLicence in Physics in 1893 and secondposition in mathematics in 1894 whilstliving in Paris under great privations. In1893 she carried on some research workon the magnetic properties of steel underProf. G. Lippmann, a Nobel Laureate inPhysics and came in contact with Prof.Pierre Curie of the Ecole de Physique etde Chimie, Paris, a great authority onmagnetism.

From 1896 she carried on thechemical analysis of numerous uraniumminerals found in Prof. Becquerel’sInstitute and other laboratories in Parisand made a striking observation that theuranium content of these minerals andtheir power to discharge a charged goldleaf electroscope do not go hand in hand.The power to discharge a gold leafelectroscope, which is caused by theradioactivity of the minerals and theionisation of the surrounding air, may belarge, specially of pitchblende, even afterthe separation of uranium. By that time,i.e. in 1895, she was married to Prof.Curie who realised the importance of theinvestigations undertaken by his wifeand joined her in these researches. Thehusband tackled this problem from thephysicist’s point of view andconcentrated on the determination of theproperties of the radiations given out. Heand others proved that the radiations

emitted by radioactive bodies consist ofa α -particles, positively charged,

consisting of helium, β -rays which arenegatively charged and γ-rays, similar tox-rays, are given out. Madame Curiedevoted herself to the chemicalmanipulation of separating largeamounts of extraneous substancesdealing with one ton of pitchblendesupplied by the Austrian Governmentfrom which uranium was separated. InApril 1898 she came to the conclusionthat pitchblende contains an unknownelement, much more radioactive thanuranium. The problem was to separatethe active material from pitchblende bychemical group separation and fractionalcrystallisation. The radioactivity of theproducts was determined by theelectrometer method. The laborious andthe tedious chemical separation wasundertaken by Madame Curie. Oneevening after returning to theirlaboratory in the Ecole de Physique et deChimie, the Curies were pleasantlysurprised to find that their radioactiveproducts were emitting light in the darkroom.

Discovery of Radium by Pierre andMadame Curie

In June, 1898 a radioactive element wasobtained in bismuth sulphide precipitateand was named polonium after the nameof the motherland of Madame Curie. InDecember, 1898 the discovery of radiumin the barium sulphate precipitate wasannounced. This impure radiumpreparation showed a radioactivity whichwas million times greater than that ofuranium.

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A third radioactive element wasdiscovered in the ammonium hydroxideprecipitate containing ferric and rareearths compounds by A. Debierne in1900, who was helping Pierre andMadame Curie. They called this productactinium, which was also independentlydiscovered by O. Giesel (1852-1927), whowas a chemist in a quinine factory inBrunswick. It has been reported thatGiesel also prepared and sold radiumbromide and his own breath was foundto be radioactive, although he lived over25 years after the discovery of actinium.Madame Curie presented her thesis forthe D.Sc. degree in the Sorbonne in 1902embodying her researches on radiumand radioactivity, and the same waspublished in the following year. In 1902she determined the atomic weight ofradium by precipitating 0.09 of radiumchloride with silver nitrate and obtaineda value of 225 as the atomic weight ofradium. Again, in 1907, working with 0.4of radium chloride, she found the atomicweight to be 226.4 taking silver as 107.88and chlorine 35.46. The eminentauthority on determination of atomicweight, Prof. Honiogschmid of Vienne, in1911, obtained a value of 225.95. Aston’smass spectograph indicated the value as226.1. The accepted value today is226.05. In 1910 Madame Curie andDebierne isolated metallic radium byelectrolysing a solution of radiumchloride with a mercury cathode. Themercury was separated from theamalgam by distillation.

Radioactivity was intensely studiedall over the world, specially by Rutherford(1871-1937) in Canada and England,

Soddy (1877-1956), Fajan, Boltiwood, O.Hahn and others. Rutherford studied theactivity of uranium and thorium andreported in 1899, that the rays emittedby uranium were of two kinds (i) thosestopped by thin sheets of aluminiumwhich he called α -rays, and (ii) the otherrequiring much thicker sheets of

aluminium designated as β -rays, whichare deflected by a magnetic field.

Madame and Pierre Curie reported

in 1900 that β -rays carry a negativecharge. Becquerel, in 1900, by deflectionin electric and magnetic fieldsdetermined the velocity (1.6 × 10 cm. persecond) and the ratio of charge to mass

(e/m = 3 ×1017 e.s.u./g of β -rays). Thesevalues are of the same order ofmagnitude as those for cathode rays.Strutt (4th Baron Rayleigh) in 1901 andCrookes in 1902 suggested that α -rayswere positively charged particles ofrelatively large mass. This was confirmedby Rutherford in 1903. Villard discoveredthe rays which were called γ -rays byRutherford. They are more penetrating

than β -rays and are not deflected bymagnetic field.

In 1910 Madame Curie couldprepare one gram of radium frompitchblende after great efforts andpresented this valuable material to herlaboratory. In 1920 she was invited bythe women of America and manyhonorary degrees and distinctions wereshowered upon her, and the women ofAmerica subscribed for the purchase ofanother gram of radium for herinstitute.

13MADAME MARIE CURIE –RADIOACTIVITY AND ATOMIC ENERGY

Madame Curie, First WomanProfessor of the Sorbonne and twiceRecipient of the Nobel Prize

In 1903 the Davy Medal of the RoyalSociety of London was awarded toProfessor Pierre and Madame Curie. TheNobel Prize of 1902 in Physics was firstawarded to Prof. Becquerel and PierreCurie, who represented to the NobelCommittee that the discovery of radiumwas as much due to him as to MadameCurie, and, the Committee agreed toaward half of the Nobel Prize to thehusband and the other half to the wife.In April, 1906 Pierre Curie was killed ina street accident in Paris. The authoritiesof the University of Paris appointedMadame Curie as Pierre Curie’ssuccessor to the Chair of GeneralPhysics at the Sorbonne. This was thefirst time that a woman was appointedas University Professor. In 1911 MadameCurie was awarded the Nobel Prize inChemistry. Thus she was the onlyrecipient of the Nobel Prize twice inscience.

Since 1900 the physiological effect ofradium rays was investigated by thePasteur Institute of Paris and the ParisUniversity jointly established a radiuminstitute known as Pavillon Curie withMadame Curie as the Director of PhysicalSciences, which was ready foroccupation in July 1914-1918. MadameCurie installed X-ray equipment formilitary purposes in 20 motor cars and200 hospitals in different parts of Francefor the trreatment of the wounded.

From her research institute 483scientific communications of which 34

were theses and 31 publications in thename of Madame Curie appearedduring the period 1919 to 1934. DoctorReguad, Director of the Biology andMedicine Branch of the Pavillon Curietreated 8,319 patients from 1919 to1935. Baron de Rothschild and LazardFreres and an annonymous donorcontributed 3.5 million francs to theCurie Foundation.

Life Pension Sactioned by FrenchGovernment in 1923

On December 26, 1923, i.e., 25 yearsafter the discovery of radium, the FrenchGovernment voted 40,000 francs asannual pension to Madame Curie withthe right of inheritance to her daughtersIrene and Eve.

Prof. Regaud wrote: ‘Madame Curiecan be counted among the eventualvictims of the radioactive body which sheand her husband discovered’.

Death of Madame Curie caused byRadioactive Emanations

In 1934 she became seriously ill andproceeded to the SancellemozSanatorium where she died. The Officer-in-Charge, Doctor Tobe recorded: ‘Thedisease was a plastic perniciousanaemia of rapid, feverish development.The bone marrow did not react, probablybeacuse it had been injured by a longaccumulation of radiation’. Due toconstant exposure to the highly toxicrays from radioactive substancesinvestigated by them, Irene and herhusband also died prematurely.

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Madame Curie – a brilliant Directorand Lecutrer

Prof. Einstein stated: ‘Marya Curie is ofall the celebrated beings the only onewhom fame has not corrupted’.

I had the honour of working in herinstitute for two years – 1917-1919, andI found that she took great pains inpreparing university lectures withexperimental demonstrations in whichher daughter Irene helped her. Afterreceiving the Nobel Prize with herhusband, Prof. Curie Joliot, Irene visiteddifferent countries and visited India in1950.

Prof. Jean Perrin, the Nobel Laureate,who was also my teacher, frequentlystated: ‘Madame Curie is not only afamous physicist, she is the greatestlaboratory director I have ever known’.During this period a galaxy of brilliantmathematicians and scientists, HenriPoincare, Appel, Painleve, Le Chatelier,Bouty, Lippmann, Haller, Behal, G.Bertrans, Roux, Delepine, Caullery,Urabain, Langevin, Duclaux, Job,Matignon, Jungfleisch, Pierre andMadame Curie, Mouton, Fabry, D.Berthelot, Moureu, Dufraisse, Grignard,Fournier and others were teaching inParis.

ATOMIC DISINTEGRATION

The collision of fast α -particles, protons,deuterons or neutrons with atoms ofother elements may cause the breakingof the nucleus. Rutherford reported in1919 and 1920 that nitrogen exposed α -particles emit long range protons whichcame from the nitrogen nucleus.Similarly, Rutherford and Chadwick in

1921, Blackett in 1922 and Harkins andRyan in 1923 demonstrated thedisintegration of atoms by the cloudchamber method. When α-particleshaving mass 4 and charge 2 bombardnitrogen atom, mass 14 and nuclearcharge 7, they enter the nucleusproducing a particle of mass 18 andnuclear charge 9, which is an isotope offluorine. This nucleus emits a proton,mass 1 and charge 1, producing anucleus of mass 17 and charge 8, whichis an isotope of oxygen. In 1932, Cockroftand Walton disintegrated lithium intohelium. This was the first artificialatomic disintegration by bombardmentwith high energy protons from hydrogenionised in a discharge tube andaccelerated by high potential difference.In 1933, F. Joliot and Irene Curie observedthat both positive and negative electronsare emitted by thin layers of berylium,boron and aluminium bombarded byparticles from polonium. In 1934, theyreported that the emission of positronpersisted even after the removal of thesource of α -particles. This was the firstdiscovery of artificial radioactivity.

Fission of Uranium to Barium byOtto Malhn and Influence ofChemical Evidence in Fission

E. Fermi and collaborators, bybombarding uranium, atomic number92, with slow neutrons obtained bypassing through water or paraffin wax,thought that they had obtained anelement of atomic number 93. Theyreported similar results with thorium in1934, but Frau Ida Noddack criticisedFermi’s chemical evidence and stated: ‘It

15MADAME MARIE CURIE –RADIOACTIVITY AND ATOMIC ENERGY

is conceivable that in the bombardmentof heavy nuclei with neutrons, thesenuclei break up into several largefragments which are actually isotopes ofknown elements, not neighbours ofirradiated elements’. O. Hahn andStrassmann in 1938, by co-precipitatingthe solution of the product of thebombardment of uranium with neutronswith a barium salt solution, thought thatthey had obtained an isotope of radium.

After β -ray decay, the products of thebombarded material were precipitatedwith lanthanum. Hence, the authorsregarded them as the actinium isotopes.Madame Joliot Curie and Savitch, in1937, reported that the bombardedproduct concentrated with lanthanumrather than with actinium.

Early in 1939, Hahn and Strassmannconcluded that their supposed radiumwas actually barium, and from chemicalevidence they concluded that theiractinium and thorium were reallylanthanum and cerium. The authorsstated that their experimental resultscontradicted the accepted views innuclear physics. Lise Meitner, who wasa collaborator of Prof. Hahn for a numberof years in Berlin, and O.R. Frisch, in1939, reported that nuclear physicsmust give way to chemistry and stated:‘On the basis of present ideas about thebehaviour of heavy nuclei, an entirelydifferent and essentially classical pictureof these new disintegration processessuggests itself. It seems possible that theuranium nucleus has only small stabilityof form and may, after neutron capture,divide itself into two nuclei of roughlyequal size.

It was soon discovered that thefission of uranium by neutrons liberatesa large amount of energy according toEinstein equation: E = Mc2 where E =energy liberated; M = mass destroyedand c = the volocity of light. Both isotopesof uranium U235 and U238, are split by fastneutrons but U235 is broken up by slowneutrons. In this process, more neutronsare liberated, but the fast neutronsescape quickly and it is only the slowneutrons which are effective for breakingU235 and the creation of an atomic bomb.

Discovery of Transuranium Elements

In modern times increased neutronfluxes are being achieved as nuclearreactors are improving and 12 newelements beyond uranium have beenisolated. The first four of thesetransuranium (94), americium (95) andcurium (94), americium (95) and curium(96) can be manufactured in kilogramswhilst californium (98) in grams. Thechemistry of berkelium (97) has beenstudied with submicrogram amountand, hence, this element along witheinsteinium (99), fermium (100), has onlybeen obtained in traces. The elementsupto fermium (100) are formed from U238

by succession of neutron capture and β -ray decay as shown by the reactionleading to the discovery of neptuniumand plutonium.

It has been found that elements ofatomic number of 100 or more decay byspontaneous fission with very short halflife, so that their preparation cannot beachieved by exposing uranium ortransuranium elements to a reactor or

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more rapidly by exploding a thermo-nuclear device in a suitably sealedunderground cave and processing thedebris. Such elements are prepared bybombarding plutonium, curium orcalifornium with boron, carbon, nitrogen,oxygen or neon ions accelerated in acyclotron or linear accelerator. The yieldsof mendelevium (101), nobelium (102),lawrencium (103) and element 104 areextremely small. Along withtransuranium elements, fair amounts oftechnetium (43) and promethium (61) areformed as fission products in nuclearreactors. Polonium 210 and actinium 227can be readily synthesised by neutronirradiation of bismuth and radiumrespectively.

Atomic Fission Markedly IncreasesProduction of Highly DangerousRadioactive Materials

Before the fission of uranium by neutronin 1939, the amount of radioactivematter in use in the hospitals andlaboratories throughout the world wasonly equivalent to a few hundred gramsof radium of atomic weight 226. Today, alow power (10 megawatt) nuclear reactorfed with natural uranium will producefission products giving out α -radiationsequivalent to one ton of radium togetherwith α -particles emitting transuraniumelements equivalent in activity to 200grams of radium. The generation of largeamount of radioactivity is highlyhazardous and the investigations of thechemical properties of the new elementsare not straightforward because of theirradioactivity, which is more intense forthe higher elements. The radiations

emitted have two importantconsequences relating to health hazardand to their chemistry. The first is thatthey are among the most toxic substancesknown to man because of the irreversibledamage to tissue caused by suchmaterials. When ingested, they areselectively retained in critical organs inthe body. Plutonium, for example, tendsto concentrate in the bone; otherelements in the series are retained in thekidneys or in the gastrointestinal tract.The high toxicity becomes immediatelyapparent when one compares themaximum permissible concentrationsper cubic metre in air for continuousexposure, assuming a 40-hour week withthose for the more conventional poisons.The figures for carbon monoxide andhydrocyanic acid are 100 mg and 10 mgrespectively while those for 239Pu and241Am are 3.1 x 10–8 mg and 1.8 x 10–9 mgrespectively many orders of magnitudesmaller than those for hydrocyanic acid.

Chemistry played a major part in thediscovery of fission process by identifyingbarium as one of the products of thermal-neutron bombardment of uranium.Chemical processes have also played anessential role in the application of thefission process to the production ofnuclear power. These processes involvethe treatment of several thousand tonsof uranium per annum; this tonnage iscomparable to that of the metals, mercuryand silver, substantially lower thanelements such as arsenic, tin and nickel,yet rather larger than gold, beryllium andtantalum.

Two sequences of chemical processesare involved. In the first, ore concentrates

17MADAME MARIE CURIE –RADIOACTIVITY AND ATOMIC ENERGY

(largely U8O3) are converted to nuclearfuels, uranium metal or dioxide. In thesecond, the nuclear fuels, after removalfrom reactors, are treated for the recoveryof useful constitutents, such asplutonium or fission-product strontium.The radioactivity in the first category isrelatively low, but in the second veryhigh.

Thorium as Fissionable Material

Since the application of uranium inatomic fission as a power source hasbeen developed to such an extent,attention has been directed to thoriumwhich is more abundant in nature thanuranium, as a possible source of thesecondary nuclear fuel U233. Accordingto J. Paone (1960) an important potentialuse of thorium is its application in thefield of nuclear energy. By the capture ofslow neutrons Th232 is converted to Th233

a negative beta particle being emittedwith a 23-minute half life. The productof Th232 is protoactinium, which is alsobeta active with a half life of 27.4 days. Itdecays into fissionable U233 and a longlived α -particle with 1.63 × 105 years halflife. Thus, the thorium nucleide, uponbombardment by thermal or slowneutrons, becomes eventually a potentialnuclear fuel material capable ofinitiating a chain reaction. Nuclearreactions employing a blanket of thoriumaround the reactor are capable undercertain conditions of producing as muchand possibly more fuel than is consumedin fission. A number of major reactionprojects proposing to use thorium havebeen under way for several years in theUSA.

Atomic Energy not yet in the Pictureof World Energy Resources

The discovery of the neutron fission ofuranium to barium and opther elementsin 1939 by Prof. Otto Hahn withliberation of tremendous energy has ledto fabulous activity and expenditure allover the world for obtaining atomic energyfor the use of man. But, uranium occurson the earth’s surface to the extent of 4grams per ton of the earth’s crust, whilstthorium, another fissionable element, isthree times more abundant. Moreover,0.7 per cent of natural uranium isuranium 235 which actually breaks upin energy production. Although, 12 newtransuranium elements have beensynthesised in the last 26 years, theconsensus of expert opinion seems to bethat even on the basis of the mostoptimistic assumption about the futurerate of nuclear developments, thecontribution of atomic power until 1975to growing energy demands will bemarginal. (The Petroleum Handbook, 4thedition, London, 1959, page 20).

‘Nuclear power offers no panacea forthe world’s energy problems. Theadoption of fission power will be slow andits rate will depend ultimately on theexhaustion of fossil fuel reserves. Fusionpower, while potentially having manyadvantages over fission power includingan inexhaustible fuel supply fornegligible cost, has not yet beenestablished as feasible and its costscannot be reliably assessed. Both typesof nuclear power are uniquely adaptedto the generation of electrical power andless so to the production of other formsof energy, such as those now used in

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comfort and process heating or in landtransportation. Thus, a radical changein existing energy consumption patternsis required before the fossil fuels arefinally enhausted.’ (Robert C. Axtmann,pp. 488-495 in The Population Crisis andthe Use of World Resources, edited S.Mudd, 1964, The Hague, Dr W. Junk,Publishers).

Beginning of Atom Bomb

After the beginning of the Second WorldWar in 1939, Prof. Otto Hahn of Berlinapproached Hitler and informed him thathe was in a position to manufacture apowerful bomb from his discovery ofatomic fission. Hitler asked him howmuch time he would take for this purposeand Hahn replied that it would take twoyears. But, Hitler was impatient and hestated that he had no use for a discoverywhich cannot prolduce tangible resultwithin six months.

On the other hand, after theoccupation of Denmark by Hitler, NeilsBohr, the great Danish atomic physicisthad to leave his own country for USA ashe was a Jew. But, before he leftDenmark, he discussed the details of

atomic fission with Lise Mertner who wasassociated with Hahn in atomic fissionstudies and who being a Jewess wason her way to Sweden from Berlin.After reaching USA, Bohr contactedA. Einstein, who also was of Jewish originand a Professor in the PrincetonUniversity as a nautralised Americancitizen. These two great men discussedthe fabrication of the atomic bomb andEinstein wrote to President Roosevelt totake up this work. Roosevelt consultedChurchill, the Premier of the UnitedKingdom, who was encouraged by LordCherwell (Prof. Lindemann), Churchill’sscientific adviser. Also, Churchill sentsome of his able atomic pysicists,mathematicians and engineers to join theUSA experts. This tremendousundertaking, which was extremelydifficult in execution, resulted in theconstruction of atomic bombs under theleadership of R. Oppenheimer, anotherJew from Germany and settled in theUSA. Under the Presidentship of Truman,the two bombs fell on Hiroshima andNagasaki in 1945, and, thus, began theatomic age with all its complications anddangers.

Acharya JagadishChandra Bose: His Lifeand Work (1858-1937)*

D.S. KOTHARI

ChairmanUniversity Grants CommissionNew Delhi

CHARYA Jagadish Chandra Boseoccupies a high, almost unique,place in the recent history of

Indian science. He was an investigatorof uncommon courage, resourcefulnessand dedication. Bose’s scientific workbroadly falls under three periods. From1894 to 1899 he was almost entirelyconcerned with the study of electricwaves; between 1899 and 1902 he shiftedfrom the physical to the biophysical field,and beyond 1903 he was occupied withthe study of plant-responses underphysical stimuli of various types. Forthese studies he developed andconstructed his own instruments whichwere remarkable for their originality andextreme sensitivity. Bose founded theBose Institute in Calcutta in 1917. Hecontinued to be the Director of theInstitute till his dealth in 1937. Bosevisited Europe many times, and Americatwice, on lecture tours. He was elected aFellow of the Royal Society in 1920, andCorresponding Member of the Academyof Sciences, Vienna, in 1929. He was the

A

General President of the Indian ScienceCongress in 1927. He served on theCouncil for Intellectual Co-operation ofLeague of Nations from 1926 to 1930.

* * * * *

Bose was born on November 30,1858, in the town of Mymensingh in EastBengal** . (His father, Bhagwan ChandraBose, was at the time Duputy Magistrateof the place). He died on November 23,1937, at the age of 79 years. (He wassurvived by his wife Smt. Abala Bose. Shewas the daughter of Shri Durga MohanDas, a leading advocate of the CalcuttaHigh Court). He received his primaryeducation at the local school atFaridpur; his father did not send him tothe English school which was there inthe same town. Later, he joined the St.Xavier’s School in Calcutta, and theCollege, from which he graduated at theage of 20. He subsequently went toEngland and joined the LondonUniversity to study medicine. Heattended some lectures by the famouszoologist, Ray Lancaster. Due partly toreasons of health, he left London to jointhe Christ College at Cambridge. Hestudied for the Natural Science Tripos,and attended lectures, amongst others,by Lord Rayleigh (Physics). He took theTripos (Cambridge) and B.Sc. (London)in 1884. On his return from England hewas appointed Professor of Physics in thePresidency College, Calcutta, in spite ofserious opposition from the thenEducation Department. Bose had to doas much as 26 hours of lecture and

* Reprinted from ‘School Science’, Vol. 3, No. 1, March 1964**Now in Bangla Desh

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demonstration per week. (This was muchmore than what was normal for hisBritish colleagues in the same college).He retired from the college in 1915.

Acharya Jagadish Chandra Bose (1858-1937)

It was probably at the age of about35 that Bose seriously made up his mindto dedicate himself completely to thepursuit of science and scientificresearch. No grant at the time wasavailable to him for research work. Thelaboratory in the Presidency College,Calcutta, was poorly equipped andsometimes Bose had to construct hisapparatus from his own personalresources. It was several years later thatthe Government sanctioned for hiswork in the college an yearly grant of

Rs. 2,500. Bose’s earliest research workwas concerned with electric waves andtheir interaction with matter. Electricwaves were first produced in thelaboratory by Heinrich Hertz in 1888 inhis epochal experiments. The existenceof these waves had been predicted byMaxwell about 20 years earlier on thebasis of his extremely far-reaching andextraordinarily fruitful (as later workshowed) electro-magnetic theory. It hasbeen sometimes said that Bose was ledto the study of electric waves, afterreading a paper by Sir Oliver Lodge on‘Heinrich Hertz and has Successors’(1894). From the very beginning Bose’sremarkable physical insight, and hissuperb ingenuity and resourcefulness inexperimentation were apparent. Hesucceeded in generating waves of wave-lengths much smaller than what Hertzand others had done. He produced wavesof about half-a-centimetre in wave-length. Because of this he was able toinvestigate in considerable detail the‘optical’ properties of electric waves, suchas refraction, polarisation and doublerefraction. He determined the refractiveindices of many substances and alsoinvestigated the influence on totalreflection of the thickness of the air-gapbetween two dielectric slabs. In thepaper published in the Proceedings of theRoyal Society in November, 1897, heobserved “It is seen from the above, thatas the thickness of the air-space wasgradually increased, the reflectedcomponent increased, while thetransmitted portion decreased. Minimumthickness for total reflection was foundto be 8 mm”. He also verified that the

21ACHARYA JAGADISHCHANDRA BOSE

thickness of the air-gap, for which totalreflection disappeared, increased withthe wave-length. It may be mentionedthat Bose’s first paper entitled ‘OnPolarisation of Electric Waves by DoubleRefracting Crystals’ (he tried beryl,rocksalt, etc.) was published in May,1895, in the Journal of the Asiatic Societyof Bengal. In 1897 Bose gave a lecture atthe famed Royal Institution, London. Itis interesting (and also instructive) torecall that the demonstration apparatusexhibited at the lecture, which inpresent-day terminology may bedescribed as a (simple) microwavespectrometer complete with transmitterand receiver (improved type of coherer),was constructed in Calcutta and takenby Bose with him to London. Theoriginality and simplicity of theapparatus employed by Bose in hisexperiments were most remarkable. Forinstance, he demonstrated thepolarisation of electric waves by thesimple device of ‘interleaving the pagesof a Bradshaw railway time table withsheets of tin foil’. Again, to eliminate theundesirable reflections of electric wavesin tubes employed to guide them (as inthe case of spectrometer), he tried manydifferent coatings — in other words, hewas searching for an absorber ofmicrowaves. He found that blotting-paperdipped in electrolyte gave the bestresults. ‘Bose, in India between 1895-97,used hollow tubes of either circular orsquare section as wave-guides and wave-guide radiators on wavelengths between5 mm and 2.5 cm. His adaptation of

hollow tubes was probably based on theused of metal tubes in telescopes andmicroscopes’.* Bose also employedconical horns —he called them collectingfunnels—for concentrating the waves onthe detectors. He studied the rotation ofthe plane of polarisation, and found thata bundle of twisted jute fibres gave rightor left-handed rotation depending on theright or left-handed twist of the fibres.This constituted a ‘large-scale or macrodemonstration’ of the opticalphenomenon of the rotation of the planeof polarisation.

For the detector, Bose used thecoherer discovered by Branly and Lodge.He made considerable improvements,particularly in sensitivity and reliability.He also experimented with the point-contact-type detector consisting of ametal wire in contact with a metal plateor semi-conducting crystal. In the caseof most substances, the resistance fallswhen the detector is exposed to electricwaves but there is also a rise of resistancefor some substances such as leadperoxide and potassium. Bose found thatin the case of galena crystal the detectorwas not only sensitive to electric wavesbut also to light radiation extending frominfra-red to violet. Here, he was obviouslydealing with what later came to berecognised as photovoltaic effect. Theseexperiments dealing with the variationsin contact resistance under theinfluence of electric waves—particularlythe erratic behaviour of the system inmany cases—brought to Bose’s mind thephenomenon of electric response in

* J.F. Ramsay, ‘Microwave Antennae and Waveguide Techniques before 1900’ Proc. I.R.E.,Feb., 1958.

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animal muscle when subjected tostumuli. ‘Bose enquires whetherinorganic models may not also be devisedwhich will satisfy this criterion. In thisway he was able to construct models inwhich mechanical and light stimuliproduce electrical responses. Theproportionality which exists betweenintensity of stimulation and electricalresponse, the gradual appearance offatigue in response after repeatedstimulation, from which the systemrecovers after it is given sufficient rest,the increase of response on treatmentwith one set of chemicals and itsinhibition by another set, are similar towhat occurs in living tissues. We shalldescribe here only one of his models : itis made of two wires of pure tin, whoselower ends are clamped to an eboniteblock; the upper ends pass through anebonite disc, and are joined throughbinding screws to the two terminalsof a sensitive galvanometer. Thearrangement fits into a cylindrical glassvessel, filled with distilled or tap water.On giving one of the tin wires a sharptwist, an electric current flows from thewire through the galvanometer system.The amplitude of response is enhancedwhen a small quantity of sodiumbicarbonate is added to the distilledwater; on the other hand, if oxalic acidis added to the water the response isabolished. Many of the effects observedin animal tissues under stimulation, viz.,of the opposite effects of small and largedoses of a chemical poison, etc., could

be obtained with this model of Bose.*Mention here may also be made of theinteresting analogy between theexcitation of nerve and the passivity ofiron dipped in strong nitric acid. This wasinvestigated in great detail by Lillie (1920-36) and later by Bonhoeffer.** The firstsuggestion came from W. Ostwald in1901. Another interesting model is dueto Bredig (1903-1908) in which theoscillations of a mercury drop placed ina hydrogen peroxide solution appear(outwardly) to resemble the rhythmicpulsations of an animal heart.

These investigations gradually ledBose to the formulation of hisfundamental concept (and in thiscontext it is relevant to call attention tohis early training in physiology andmedicine) that basically the response,under stimulus, in the non-living (e.g.metal) and the living (e.g. animal muscle)is of the same nature, though they differin their level of complexity. From about1903 onwards Bose investigated withgreat ingenuity, vigour and persever-ance the response phenomena in plantswhen exposed to various kinds of stimuli,e.g. mechanical, electrical and chemicaland also light radiation. He regarded thatthe response phenomena in plants liebetween those exhibited in inorganicmatter and in animals. He developed andconstructed in his own laboratory specialinstruments for the purpose ofmeasuring almost every type of plantresponse. The rate of growth of plants is,crudely speaking, of the order of 0.1 –

* D.M. Bose, Jagadish Chandra Bose: Birth Centenary Series III. Science and Culture, 24, 5 (1958).p. 215.

**R.R. Bonhoeffer, ‘On the Passivity of Iron’. Corrosion, II (1955). See also R. Fatt, ‘Physics of NerveProcesses’. Reports on Progress in Physics, XXI. (1958), p.112.

23ACHARYA JAGADISHCHANDRA BOSE

0.01 mm per minute, and to measurethat he constructed many instrumentswhich he named Crescographs (crescere:to grow). The high-magnificationcrescograph consisted of a combinationof levers (in some cases mechanical andoptical) giving a magnification of about10,000. The magnetic crescograph, inwhich the small displacement of amagnet caused a large deflection in astatic magnetic system, produced amagnification of more than a million.Bose also developed several types ofautomatic recorders in which frictionbetween the recording pan and thewriting plate was eliminated by eithervibrating the plate or the stylus. Heconstructed an instrument to recordthe liberation of oxygen duringphotosynthesis in plants. He alsostudied the variations, as a result ofstimulations, in the electricalresistance of plant tissue. He was thefirst to use electric probes for thelocalisation of actively metabolisinglayers in plants.

Bose’s plant work was largely carriedout with the Mimosa plant and withDesmodium gyrans (telegraph plant, theIndian name is bon chural). He studiedeven such things as the effect of load(placed on the leaf) on response tostimulus. For instance, he observes: ‘Theeffect of load on the response of Mimosais similar to that on the contractileresponse of muscle. With increasing loadthe height of response undergoes aprogressive diminution with shorteningof period of recovery. Within limits, theamount of work performed by a muscleincreases with load. The same is true of

the work performed by the pulvinus ofMimosa’. In the case of Desmodiumgyrans he observed that the detachedleaflet continued to show rhythmicpulsations, the period being of the orderof two minutes. The pulsation occursbetween the temperature of about 17°Cand 45°C. The pulsation is affected bychemical reagents and electric stimuli.Bose also investigated the problem of theascent of sap in plants. He thought,contrary to the generally accepted viewthen and now, that this is brought aboutby peristaltic activity of the inner corticalcells in the plant stem, somewhatanalogous to the activity of the animalheart.

* * * * *It may be observed that one of the

most far-reaching concepts which hasemerged from the biological andphysiological researches during thepresent century is that all vital processesin living organisms can be (completely)understood in terms of physical andchemical laws governing materialphenomena. (It appears – some think itis certain that this is not likely to be thecase in the realm of phenomenaconcerning the mind). Towards thisrealisation Bose made a pioneering andvery important contribution. In one of thepapers read (but not published) beforethe Royal Society in 1904 he observed:‘From the point of view of its movementsa plant may be regarded in either of twoways: in the first place, as mysteriousentity, with regard to whose working nolaw can be definitely predicted, or in thesecond place, simply as a machine,transforming the energy supplied to it,

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in ways more or less capable ofmechanical explanation. Its movementsare apparently so diverse that the formerof these hypotheses might well seem tobe the only alternative. Light, forexample, induces sometimes positivecurvature, sometimes negative.Gravitation, again, induces onemovement in the root, and the oppositein the shoot. From these and otherreactions it would appear as if theorganism had been endowed withvarious specific sensibilities for its ownadvantage, and that a consistentmechanical explanation of itsmovements was therefore out of thequestion. In spite of this, however, ‘I haveattempted to show that the plant maynevertheless be regarded as a machine,and that its movements in response toexternal stimuli, though apparently sovarious, are ultimately reducible tofundamental unity of reaction’.* Andfurther, to quote from his book, PlantResponse as a Means of PhysiologicalInvestigation (1906): ‘The phenomenon oflife, then, introduces no mystical power,such as would in any way thwart, orplace in abeyance, the action of forcesalready operative. In the machinery of theliving, as in that of the non-living, wemerely see their transformation, inobedience to the same principle ofconservation of energy as obtainselsewhere; and it may be expected that,in proportion as our power ofinvestigation grows, the origin of eachvariation of the living organism will befound more and more traceable to the

direct or indirect action upon it ofexternal forces, the element of chancebeing thus progressively eliminated, asthe definite sequence of cause andeffect comes to be perceived with anincreasing clearness; and only, I ventureto think, as this is worked out, can welearn to apprehend fully the truesignificance of the great Theory ofEvolution’.

* * * * *In his papers and books Bose gives

very few references to previous andcontemporary workers. This is partly, nodoubt, due to the fact that he was inmost cases exploring new ground. Itshould also be mentioned that ‘thepriority of many of Bose’s observations,e.g. positive and multiple responses,alike electrical and mechanical, andtransmission of death excitation, isseldom given the acknowledgement due,in current literature on plant physiology…He has left behind nineteen volumeswhich form a record of the work carriedout and directed by him over a period ofnearly thirty seven years. Bose was trulya great man of science and hispioneering spirit and work have playeda vital role in the revival of scientificresearch in our country. But for all thishe was more in the nature of a loneworker — a towering but isolated peak-rather than a builder himself of a schoolof scientific research. To conclude we mayquote his memorable words spoken atthe end of the lecture at the RoyalInstitute (London) in January, 1897: ‘Theland from which I come did at one time

* ‘Plant Response as a Means of Physiological Investigation’ by Sir Jagadish Chandra Bose (1906), p.viii.

25ACHARYA JAGADISHCHANDRA BOSE

SHORT BIBLOGRAPHY

D.M. BOSE. 1958. Jagadish Chandra Bose, Science and Culture, Nov.M.N. SAHA. 1940. ‘Sir Jagadish Chandra Bose’, Obiter Notices of Fellows of

the Royal Society, 3, 1-12.PATRICK GEDDES. 1920. ‘The Life and Work of Sir Jagadish Chandra Bose, M.A.,

D.Sc. U.D., F.R.S., C.I.E., C.S.I.’, Longmans.‘Obituary Notice’. 1937. Nature, p. 1041 (Dec. 18).J.F. RAMSAY. 1958. ‘Microwave Antennae and Wave-guide Techniques before

1900’, proc. I.R.E., Feb.J.C. BOSE. 1927. ‘Collected Physical Papers’, Longmans, p. 404.——— 1902. ‘Response in the Living and Non-living’, Longmans, p. 199.——— 1906. ‘Plant Response (as a means of Physiological investigation)’,

Longmans, p. 781.——— 1913. ‘Researches on Irritability of Plants’, Longmans, p. 376.——— 1924. ‘The Physiology of Photosynthesis’, Longmans.——— Transactions of the Bose Research Institute ,1919-1937.

Nearly 100 years after Guglielmo Marconi’s first transatlantic wirelesscommunication, a group of scientists of the US-based Institute of Electronicsand Electrical Engineers (IEEE) have reported that – “the origin and first majoruse of the solid state diode detector devices led to the discovery that the firsttransatlantic wireless signal in Marconi’s world famous experiment, in 1901,was received by Marconi using the iron-mercury-iron coherer with a telephonedetector invented by Sir J.C.Bose in 1898”.

(Editor)

strive to extend human knowledge, butthat was many centuries ago. It is nowthe privilege of the West to lead in thiswork. I would fain hope, and I am sure Iam echoing your sentiments, that a timemay come when the East, too, will takeher part in this glorious undertaking; andthat at no distant time it shall neitherbe the West nor the East, but both theEast and the West, that will work together,each taking her share in extending theboundaries of knowledge, and bringingout the manifold blessings that follow inits train’.

Geddes in his ‘Life of Bose’ gives thefollowing extract from the Spectator(London) : ‘We can see no reasonwhatever why the Asiatic mind, turningfrom its absorption in insolubleproblems, should not betake itselfardently, thirstily, hungrily, to theresearch into Nature, which can neverend, yet is always yielding results, oftenevil as well as good, upon which yetdeeper inquiries can be based. If thathappened – that would be the greatestaddition ever made to the sum of mentalforce of mankind’.

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Assessment of Learningand Acquisition ofScientific Temper

N. PANCHAPAKESAN

Retired ProfessorDepartment of Physics andAstrophysics, University of DelhiK-10, Hauz Khas EnclaveNew Delhi 110 016.

E ARE at the end of the year‘World Year of Physics’. Itcelebrates the centenary of

Albert Einstein’s ‘Special Theory ofRelativity’ given in 1905. It is said thatthis theory removes absolutism andbrings in the idea of relativism. Everyinertial observer has his own time andevent simultaneities. No one observer isspecial in any way. Put another way,everyone is unique! Philosophers saythat this (along with other events) hasled to ethical relativism. No one wants totake a definite stand against or for anyabsolute value or principle. ButEinstein’s theory of relativity also pointedout and discussed invariances andcovariances which exist in the universe.Universal and relative concepts livetogether.

This is what we need to keep in mindwhen we look at any problem, includingAssessment. There is a common level ofobjectives and aims and at the same timeeach learner has his own space-time, hisown world. These distinctions becomevery important when we haveinstitutional frameworks for imparting

education. Even in the best of cases, theaims of persons in different segments orlayers of the system are not identical.Perceptions vary widely depending on theenvironment. A teacher is not perfect.She has to worry not just aboutcommunicating but also about herstudents doing well in the examinations.To remove subjective distortions, a fairlyinflexible system is set up and adheredto meticulously, almost obstinately. Theresult is often counter- productive to theaims of education. If the society or thesystem was perfect, as envisaged by atheoretical model, then there is noproblem. However in a realistic, humansituation, there are deviations,departures, imperfections, which can beignored only at our peril. What we needis a perception, an understanding of thedeviations (imperfections ?) in any givensituation. By definition these can not bemodeled in an ideal or perfect way.

This is where ‘Science Education’ceases to be a ‘natural science’ andbecomes a ‘social science’ with all itsheartaches and uncertainties. We lookat the qualitative differences between thenatural and social science. Acquiringscientific temper is akin to learningvalues and is really a part of socialscience. Science education has very littleto do with developing a scientific temper.The discussion will be against thebackground of the ‘Hoshangabad ScienceTeaching Programme’ which ended inMadhya Pradesh a few years ago.

1. Introduction

It is ironic that I should have beenchosen to speak on assessment. I have

W

27ASSESSMENT OF LEARNING ANDACQUISITION OF SCIENTIFIC TEMPER

a great aversion to judging people. I havenot been on any committee or groupinvolved with the NET examination of theUGC or CSIR or the admission committeein my department. It is not that I haverefused to do these things, but I wasnever asked. Maybe others guessed myreluctance or had doubts about mycompetence. But somehow I got involvedin assessment with HSTP.* Studentswere doing so badly that it was decidedthat they should be marked on the curve.I came up with simple minded analysisof marks which could then be modifiedto get a decent distribution (sophisticatedfudging !). Otherwise all the studentswere in a pile at the bottom. This wasmore than 25 years ago. After that theHSTP has grown and I am sure, changed.I do not know if the analysis was changed,modified or continued. Anyway that isthe only justification for my standingbefore you, talking about assessment inschools. Of course, I have been forced toassess my own students at theuniversity.

My first observation follows naturallyfrom what has been said above. Thesource group in HSTP had (or liked) todo things they were never qualified for,but had secretly wanted to do ! We hadpeople getting interested in drawingsketches, designing book lay outs etc. Inmany cases their efforts were verycreative, good and successful. That issomething the formal systems neverencourage or permit. I think that is a pluspoint for People Science Movements likeHSTP.

2. Imperfect Institutional Frameworks- Need More Assessments

My main theme in this talk is that thetime has come for the workers in the fieldof education to go to the second stage.The first stage was to agree on childcentering. The National CurriculamFramework (NCF) has already done that.However, child centering is an idealconcept. It requires perfect conditions,low student teacher ratio, highly qualifiedand motivated teachers etc. Going to thesecond stage is to recognise theimperfections and try to work in a nonideal system. A lot of optimisations willhave to be done. We might recall thatwhatever progress the subject ofeconomics has made, is because of therecognition of imperfect markets andimperfect competition, and not workingwith the idea of a hidden hand of AdamSmith. A physical law is same for everyobserver but each observer uses his ownspace- time to work in.

Start with an example. A class has30 students instead of 5 or 6. Then :

● It is necessary to have students ingroups of 5 or 6.

● One needs attendance registers

● One needs submission of class andhome work and its correction andevaluation.

● One needs periodic and finalevaluation.

None of this is needed if one had avery small number of students.

*Hosangabad Science Teaching Project

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Let us take an example from HSTP of30 years ago.

● Unqualified Teachers

● Absence of Kit

● Ignorance of Decimals

● Non Suitable examination

● Lack of language fluency amongstudents

These were addressed by

● Having monthly meetings withteachers

● Getting involved in designing/purchasing and distributing Kit.

● Writing and including a chapter onDecimals.

● Designing and conductingexaminations in theory andpracticals.

Linguistic Ability could not beaddressed. It was way out of our ambit.Many other problems were never tackledthough one was aware of them. Some ofthese were

● Parental anxiety about doing well inMedical (PMT) and Engineering(JEE) entrance exams.

● No substantial advantage offered byHSTP in performance in 9th Classand above.

The old system may not be goodeducation but over the years aninformal parallel system of well checkedguidelines and suggestions hasdeveloped on how to score highly inexaminations!

3. Assessment—An Overview

The topic of this paper is an importantpart of educational policy and has beendiscussed ably in the NationalCurriculam framework (NCF). It may beuseful to begin with what they say andtheir conclusions. By and large they arenon controversial.

“Education is concerned withpreparation for meaningful life andevaluation should provide feedback onthe success in implementing such aneducation. Current processes ofassessing a very limited range of facultiesare highly inadequate. Even the limitedpurpose of providing feedback onscholastic and academic developmentcan be achieved only if the teacher isprepared before the course of teachingwith the techniques of assessment, theparameters of evaluation and the kindsof tools that will be employed. In additionto judging quality of student’sachievement, a teacher has to collectanalyse and interpret performance onvarious items of assessment tounderstand the learning in differentdomains. The purpose of assessmentis to improve teaching-learningprocess and materials, and to reviewthe objectives one began with, in thelight of capabilities of learners asrevealed by testing. In the evaluationof learning we should also haveparameters which encompass creativity,innovativeness, development of thewhole being, attitudes to learning andability for independent learning.Assessment and examinations must be

29ASSESSMENT OF LEARNING ANDACQUISITION OF SCIENTIFIC TEMPER

credible and based on valid ways ofgauging learning.” (emphasis has beenadded and considerable editing has beendone)

The examination reform committee,associated with NCF, had recommendedContinuous and ComprehensiveEvaluation (CCE) coupled with teacherempowerment. The NCF, however, urgescaution as CCE places a lot of demandon the teacher’s time and ability tomaintain records. This is an example ofwhat I would like to call recognisingimperfections on the ground. CCE is bothgood and bad. Niels Bohr, the famousphysicist had several famous argumentswith Albert Einstein and often came outvictor. He said “A great truth is one forwhich the truth and its opposite, bothare true”. CCE seems to fall into thatcategory. Social science is full of greattruths! ( Physics has only a few, likeParticle — Wave duality.)

The Examination reform committeealso gives suggestions on nature ofquestions which should be asked. Theirdetailed recommendations on differentways of testing different classes (in thecontext of CCE) can be very useful, if notused rigidly or forcibly. It is made quiteobvious at various places that making oftests ensuring their reliability, credibilityand validity is a specialised job requiringprofessionals. The scarcity of suchprofessionals is a matter of deep concernin our country. The corporate sector alsoneeds evaluation instruments. They arenow coming into the country as part ofcollaborations with foreign institutions.There is however a total lack ofindigenous effort in creating instrumentsfor academic testing.

4. Scientific Temper, Science andSpirituality (or Religion)

Before we can discuss scientific temperwe have to deal with the differencebetween natural science and socialscience. ( sometimes referred to as hardand soft science) This requires a briefreview of the world view of a person andthe place of different types of knowledgein that world view. Broadly speaking, wecan talk of an inner and an outer worldfor a person.

I, the thinker, am at the centre of theinner world. I receive continually, frombirth, perceptions which serve to definemy world view. Free will or capacity tomake a choice is assumed. In decidingor making a choice, one needs a valuesystem, part of which is inborn and partcomes from outside due to parental andother societal influences, including, ofcourse, faith or religion. The ordering ofone’s perceptions defines a flow of time,a personal time which can be related tophysical time of the outside world.Communication with the outside worldby speaking, listening, reading (use oflanguage ) coupled with logic enables theconstruction of the outside world. As isclear the centre of description of the innerworld is oneself. The details of many ofthe above processes, like constructionof outside world, are subjects of study inthemselves. Every generation ofphilosophers re-examine and writetreatises on them.

The outer world is the objective orimpersonal world which existed beforemy birth, holds me in it now and willcontinue to exist after my death. It is theworld of physics and other sciences.

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Emotion or feeling does not enter into theimpersonal description of the outsideworld. Logic and scientific method(repeatability, falsifiability) arenecessary. This world has a universaltime and history. It has no preferred orobvious centre and is accessible to everyindividual through his or herperceptions. Science is related to outerworld and decides our knowledge of it,its laws and evolution.

Spirituality is related to inner world.It does not use the scientific method orthe intellect directly. If one has todescribe it one can say that it is a feelingof nobility, elation, love, bliss guided byemotion or a refined version of emotion,yet seeming to transcend all these.

Working of Inner World

Inner world includes humanities, artsand social sciences and all other areasof outside science. Though this world isnot part of science, the scientific method,i.e. logic and reasoning, plays an essentialrole here. However, repeatability andfalsifiability do not exist; as controlledexperiments are not generally possibleand where possible have large errors ordispersions. Some times the word ‘Softsciences’ is used to describe these areaswhich include economics, sociology,political science, psychology etc.Statistical methods are crucial for theirstudy. To achieve objectivity in the studyof these subjects is not easy. Detachmentplays an essential role though perfectdetachment is not possible. Carefulauthors declare their individualviewpoints and beliefs to enable thereader to discount subjectivity and bias.

In the inner world heart, rather thanthe head, is the decider. Love, affection,kindness, elation, ecstasy play big rolein decisions. Soft sciences try to deal withsuch problems in many ways, many ofthem statistical in nature. There ishowever the difficult problem of,empirical validity’. In the absenceof experimental or mathematicalproof, validity is by personal satisfaction.One example is ‘Music Appreciation’.Here personal satisfaction is a keyfactor, though opinions of other expertsmay also play a role. Personal satisfactionis accompanied by elation or happyfeeling and decides our choice of goodmusic. The ultimate in personalsatisfaction is what is called bydifferent names: peak experience, cosmicreligious feeling, self-actualisation,brahmananda, etc.

Peak experience as a guide to truth

The peak experience plays as much rolein the outer world of science as in theinner world. This is because scientistsare human beings and the creativeexperience spans both the worlds. Therole of peak experience in science hashowever been difficult to grasp in anunambiguous way. Kepler’s laws ofplanetary motion led Newton to give histheory of gravitation. Kepler was in greatecstasy when he discovered his laws andthis convinced him of the correctness ofthe laws. He was right in this case.However, there were many otherconclusions he reached, based onecstasy, most of which were wrong. So itappears that peak experiences have tobe subjected to experimental verification

31ASSESSMENT OF LEARNING ANDACQUISITION OF SCIENTIFIC TEMPER

and validated, before their scientific truthcan be accepted.

In the inner world there is no suchway of validation. One has to live withuncertainty and try to validateconclusions to the extent soft sciencespermit you. The acceptance of authorityin the real world, however, does not seemto be based on validity alone. It is amixture of charisma, social importanceand the power wielded by the promoterof the idea. Hence use of logic, touch withreality and scientific method to theextent possible, is absolutely necessaryto tell us if the ‘emperor has no clothes!’

Logic and reason have been part ofsocial science and philosophy muchbefore modern science developed.Modern science has reinforced the useof logic and reason, now under the nameof scientific method, in soft sciences. Thismakes a person question the commandsof priests and religious books, reducingthe power of the clergy. In the frameworkgiven above there is really no conflict

between science and spirituality as theybelong to different areas, either outer orinner world. Both are part of my worldview, in my mind. There is no body-mindduality.

Scientific Temper

Scientific temper is an attitude todifferent questions that arise in normallife of a human being. Like believing insuperstition, accepting the pronounce-ments of a religious authority. These areall based on man made rules notscientific laws. ‘What your scientifictemper is’, is hence a part of socialscience. The acquiring of scientifictemper is akin to acquiring values.Science has nothing to do with scientifictemper! It is a red herring in scienceeducation, though very important fortotal education. This was seen in theHoshangabad programme. The realopposition to the new way of teachingemerged only when social sciences weretaught differently.

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Conserving Biodiversity:An ImportantEnvironmental Priority

MONIKA DAVAR

Lecturer, Department of EducationMaharaja Surajmal InstituteC-4, Janakpuri, New Delhi

IODIVERSITY refers to variety andvariability among living orga-nisms, their genetic differences

and the ecosystems in which they live.The distribution of living organisms isuneven on the earth because of differentenvironmental conditions. Countries likeBrazil, Columbia, Mexico, Indonesia,Peru, Malaysia, Ecuador, India, Zaire,Madagascar and Australia are known asmega diversity countries because of theirrich biodiversity. India alone is estimatedto have over 45,000 plants and 65,000animal species. Biodiversity as a nationaland global resource is extremelyvaluable. Biological resources once lostcannot be replaced at any cost.

WHY CONSERVE BIODIVERSITY?

The biological diversity of the planet isbeing rapidly depleted as a consequenceof human actions. An unknown but largenumber of species are already extinctwhile many others have reducedpopulation sizes. The current extinctionproblem has been called the ‘SixthExtinction’, as its magnitude compareswith that of the other five massextinctions revealed in the geological

record. The current extinction is of a moreserious nature as species are being lostat a rate that far outruns the origin ofnew species. Thus conservingbiodiversity should be the utmostpriority.

Some other important reasons forconserving biodiversity are as follows:-

● Uses to Humans: Humans derivemany direct and indirect benefitsfrom the wide variety of livingorganisms. Bioresources include allour food, many medicines, clothingfibers (wool and cotton), rubber andwood. Thus, we have a stake inconserving biodiversity for theresources we use.

● Future Resources: As knowledgeimproves, new bioresources toincrease human welfare may bediscovered and developed. Manypresently under-utilised food cropsmay become high yielding anddisease resistant varieties throughhybridisation with wild species.Genetic engineering of micro-organisms’ promises furtheradvances in the production of newcompounds and medicines. Thisfuture potential will be lost ifextinction of species continues at arapid rate.

● Adapting to Change: Another greatvalue of the variety of life is theopportunity it gives us for adaptingto change. Genetic diversity willenable breeders to tailor crops tonew climatic conditions. Amultiplicity of genes, species andecosystems is a resource that can

B

33CONSERVING BIODIVERSITY – ANIMPORTANT ENVIRONMENTAL PRIORITY

be tapped as human needs change.

● Biodiversity as an Asset: As acountry, it is important to protectour unique natural environments.India attracts tourists from all overthe world due to its wide variety ofplants and animals. The tiger, lotus,and peacock are our national icons.Some plants and animals havereligious significance for Indiansand are considered sacred.

● Ecological Services: Besidesserving as an asset to the nationand resource to humanity,biodiversity also provides ecologicalservices. Vegetation acts as a bufferand helps in maintaining movementand storage of water within thebiosphere. It also stabilises theclimate. Plants prevent soil erosion.Biodiversity also helps in regulatingthe oxygen and carbon dioxidebalance, nutrient and mineralcycling. Thus, the diversity of lifeneeds to be conserved fromecological standpoint also.

● Interdependence of Species: In thebiosphere, all organisms areinterrelated and interdependent.Each species has its own place inthe sequence of events even if itdoes not seem like an important one.If one species is eliminated, itinterrupts the flow of processes.This change affects the wholeecosystem to varying degreesdepending on the role of theorganism. In cases where thespecies lost is a key one, it can leadto complete breakdown of the wholeecosystem. An example of this is the

Baltic Sea. An increase in algalgrowth and change in fish stockshas occurred leading to undesirablechanges in the aquatic ecosystem.

● Continued Existence of thePlanet: Biodiversity not onlyprovides stability to ecosystemsindividually but also provides afoundation for the continuedexistence of a healthy planet. Whenecosystems are diverse, there is arange of pathways for primaryproduction and ecological processessuch as nutrient cycling, so that ifone is damaged or destroyed, analternative pathway can be used sothat the ecosystems continuefunctioning at their normal level. Ifbiodiversity is diminished, theecological balance of the wholeplanet will be disturbed.

● Research and Monitoring: Naturalareas provide excellent livinglaboratories for valuable researchinto ecology and evolution.Unaltered habitats are oftenessential for certain researchapproaches, providing controlsagainst which the changes broughtabout by human activities may beassessed.

● Human Responsibility for thePlanet: Irrespective of the benefitsbiodiversity provides, since humanbeings are the highest forms of lifeon this planet, they have theresponsibility to protect all otherspecies.

● Ethical Justification: On ethicalgrounds also, conserving bio-diversity is justified because one

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species on earth does not have theright to drive others to extinction.All species deserve respect becausethey are all components of ourbiosphere.

There is possibly no single particularargument which on its own providessufficient ground for maintaining allexisting biological diversity. A more

pragmatic approach, however, recognisesthat different arguments namely theutility to humanity, use in maintainingecological balance, serving as researchbase, holding potential for future andethical and moral responsibility of manfor continued existence of a healthyplanet together provide an over -whelmingly powerful and convincing casefor the conservation of biodiversity.

Green Chemistry andEducation

Obot, Ime BasseyDepartment of ChemistryUniversity of UYO, PMB 1017, UYOAkwa Ibom State, Nigeria

REEN CHEMISTRY has evolvedfrom its roots in academicresearch to become a

mainstream practice supported byacademia, industry, and government.While green chemistry encompasseshuman health and the environment, itis guided by very specific principles ofchemical practice. The interest in usinggreen chemistry and its practices hasextended internationally to become analternative to traditional pollute-and-then clean-up industrial practice indeveloping countries. This evolution ismarked by significant contributions frominstitutions with different goals that arebeing satisfied through a commonmechanism.

What is Green Chemistry?

Green Chemistry is the use of chemistryfor pollution prevention. More specifically,it is the design of chemical products andprocesses that are environmentallybenign. Green Chemistry encompassesall aspects and types of chemicalprocesses that reduce negative impactsto human health and the environment.

Green Chemistry provides anapproach focused on the principle ofmoving pollution prevention upstream to

change fundamental processes andemphasises the use of chemicalprinciples and methodologies for sourcereduction.

Why Green Chemistry?

There is no doubt that our lives havebeen enhanced by chemistry. However,environmental problems such as DDT,(Dichlorodiphenyltrichloroethanal),ozone depletion are all too familiarexamples of chemistry gone wrong. Inresponding to the growing concern,government introduced regulations tolimit pollution and exposure tohazardous chemical and materials.Green Chemistry represents afundamental shift from this modeltowards a pollution prevention paradigm.Its premise is that a benign process andproducts presents no risk.

The importance of Green Chemistryas an alternative in the developing worldcannot be overstressed. Sustainabledevelopment depends on providing goodsand services for a growing populationwithout sacrificing environmentalquality. Estimates from the UnitedNations put the world population as highas 10.7 billion people by 2050 and thisnearly doubled population creates a hugedemand for chemical goods and servicesin the near future. Much of the growthof the chemical industry is likely to takeplace in the developing world, coincidentwith the rising population. However,many of the global environmentalimpacts attributable to this populationgrowth have ties to chemical processesor products: 1

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● loss of biological species in forestand in water

● ozone depletion

● downstream pollution fromunsustainable agriculturalpractices

● the pollution of fresh and marinewaters, further depleting foodsources

● the introduction of persistentorganic pollutants into theecosystem

● changing climates, causing as yetunpredictable changes in thehydrologic cycle with manifestationsin flood, drought, sea level change,and the spread of infectiousdiseases.

The Twelve Principles of GreenChemistry 4

1. Prevention: It is better to preventwaste than to treat or clean upwaste after it has been created.

2. Atom Economy: Synthetic methodsshould be designed to maximise theincorporation of all materials usedin the process into the finalproduct.

3. Less Hazardous ChemistrySynthesis: Wherever practicable,synthetic methods should bedesigned to use and generatesubstances that possess little or notoxicity to human health and theenvironment.

4. Designing Safer Chemicals:Chemical products should bedesigned to effect their desired

function while minimising theirtoxicity.

5. Safer Solvents and Auxiliaries:The use of auxiliary substances(solvents, separation agents, etc.)should be made unnecessarywherever possible and innocuouswhen used.

6. Design for Energy Efficiency:Energy requirements of chemicalprocesses should be recognised fortheir environment and economicimpacts and should be minimised.If possible, synthetic methodsshould be conducted at ambienttemperature and pressure.

7. Use of Renewable Feedstocks: Araw material or feedstock should berenewable rather than depletingwhenever technically andeconomically practicable.

8. Reduce Derivatives: Unnecessaryderivatisation (use of blockinggroups, protection/deprotection,temporary modification of physical/chemical processes) should beminimised or avoided if possible,because such steps requireadditional reagents and cangenerate waste.

9. Catalysis: Catalytic reagents (asselective as possible) are superiorto stoichiometric reagents.

10. Design for Degradation: Chemicalproducts should be designed so thatat the end of their function theybreak down into innocuousdegradation products and do notpersist in the environment.

37GREEN CHEMISTRYAND EDUCATION

11. Real-time Analysis for PollutionPrevention: Analytical methodo-logies need to be further developedto allow for real-time, in-processmonitoring and control prior to theformation of hazardous substances.

12. Inherent Safer Chemistry forAccident Prevention: Substancesand the form of a substance usedin a chemical process should bechosen to minimise the potential forchemical accidents, includingreleases, explosion, and fires.

The Future of Green Chemistry

There is no doubt that the emerging areaof Green Chemistry has identifiedscientific principles, approaches, andmethodologies that have demonstratedthe most positive aspects of chemistry.While the successes of Green Chemistrythus far seem quite large in terms ofquantitative benefit to human, healthand the environment, they are merely thetip of the iceberg when compared to thepotential. To reach this full potential,greater awareness, adoption, anddevelopment of Green Chemistrypractices are necessary. 2

Sustainable economic developmentdepends on the chemical industry toproduce a vast array of chemicalproducts. Thus, in the future, the mainsustainability target with regard tochemicals will be to apply inherently safe

chemicals, which are unlikely to pose arisk to human health and environmenteven without specific exposure controlmeasures due to the lack of hazardousproperties. This should be particularlyvalid for open applications. In contrast,very hazardous chemicals should beauthorised and used only in closedsystems or in installation where releasesare negligible, thus posing no risk forhuman and environment.3

Green Chemistry is a dynamic matchof scientific, economic and socialinterests that leads to a future wherechemistry is viewed as fundamental toprotecting the environment. However, thesuccess of Green Chemistry, will dependdirectly on the training and dedicationof a new generation of Chemists—thestudents of today.

World Wide Web Resources 5

Some websites that may be useful forthose trying to incorporate GreenChemistry into their teaching are givenbelow:1. http://www.acs.org/education/greechem/2.http://www.lanl.gov/greenchemistry/3. http://www.epa.gov/greenchemistry/4. http://www.rsc.orq/is/iournals/current/green/greenpub.htm.5. http://www.rsc.org/is/journals/current/green/GCOO2001.htm6. http://www.chemsoc.org/networks/gcn/.

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REFERENCES

BENEDICK, R.E. 2000. “Human Population and Environmental Stresses in theTwenty-first Century” in Globaler Wandel Global Change; Kreibich, R.and Simonis, U.E. Eds; Berlin.

CHEMRAWNXlV Website: http://cires.colorado.edu/env_prog/chemrawm/.GCl Website: http://www.lanl.gov/greenchemistry/.Listserver: gci@lanl.govANASTAS, P.T. and WARNER, J.C. 1998. Green Chemistry: Theory and Practice;

Oxford University Press: New York. p.30DENNIS L.H., DAVID L.S., and JANET, M.B. 2000. Journal of Chemical Education

Vol 77 No. 12.

Hearing – A PhysicalPhenomenon

VANITHA DANIEL

LecturerDIET, KurukkathiNagapattanam, Tamilnadu

V.S. SURESH KUMAR

Lecturer in Physics (S.G.)T.B.M.L. CollegePorayar 609 307Tamilnadu

VEN IN THE quietest country side,there are still sounds, such aswind, singing birds and buzzing

insects. Sound waves, a physicalphenomenon, are sure to occur when afalling tree hits the ground. The humanauditory system enables us to hear notonly the sound produced by a falling tree,but also the birds singing in the treesand the wind blowing through theirleaves. Our auditory systems areamazingly well adapted for detecting andinterpreting an enormous variety ofinformation.

Properties of Sound Waves

Sound waves are characterised by theiramplitude, their wave length and theirpurity. These physical properties affectmainly the perceived qualities and soundlike its loudness, pitch and timbre.Varying wavelengths of sound aredescribed in terms of their frequency,which is measured in cycles per secondor hertz (Hz).

E

Frequency

The frequency of a sound is the numberof compressions per second, measuredin hertz (Hz-cycles per second). Pitch isa perception closely related to frequency.As a rule, the higher the frequency of asound, the higher is its pitch. Themaximum displacement of the wavecorresponds to amplitude and thenumber of waves per second correspondsto frequency (Fig.1).

Higher frequencies are perceived ashaving higher ptich. Humans can hearsounds ranging in frequency from a lowof 20 Hz upto a high of about 20,000 Hz.Sounds of either end of this range areharder to hear. At the other extremes,bats and porpoises can hear frequencieswell above 20,000 Hz. Low frequencysounds under 10 Hz are audible tohoming pigeons.

Amplitude

In general, the greater the amplitude ofsound waves, the louder the soundperceived (Fig. 1). The amplitude ismeasured in decibels (dB). Even briefexposure to sounds over 120 decibels canbe painful and affects auditory system.

Fig. 1: Four Sound Waves of different frequencies and amplitude

Low frequency

Higher frequency

Low amplitude

High amplitude

0.1 Second

Am

plitu

de

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The following table gives the relativeintensities of a few sounds. The thresholdintensity is taken as zero decibel.

Soft music – 40 decibels

Telephone – 60-70 decibels

Busy traffic – 70-85 decibels

Alarm clock – 80 decibels

Jet aircraft – 115-120 decibels

According to WHO Noise affectshealth and prolonged exposure to soundabove 140 decibels may produceinsanity.

Perception of high frequency decreseswith age. Preschool children are betterthan adults at hearing frequencies of2,000 Hz and above (B.A. SchneiderTrehub, Morron giello & Thorpe 1986).For middle aged adults, the upper limitfor hearing decreases by about 80 Hzevery six months (Von Bekery 1987). Theupper limit drops even faster for thoseexposed to loud noises.

Loudness

The loudness of a note depends upon theintensity of sound or the rate of flow ofenergy to the ear. But it is notproportional to it since the sensitivenessof the ear varies with the pitch. Near themiddle of the audible range offrequencies, the ear is mot sensitive tochanges of intensity which it interpretsas loudness.

Sensory Processing in the Ear

Our ears are specially designed to detectsound waves, turn them into nervesignals and send these nerve signals tothe brain which analyses them andidentifies the sound. Sound waves are

periodic compression of air, water or othermedia. When a source emits sound itbasically sets up vibration in thesurrounding medium. The vibratingsource sets up tiny disturbances inthe surrounding medium. Thesedisturbances in air cause rise and fall ofair pressure relative to the normalambient pressure. As the sound wavestravel through the medium, the soundenergy is passed on by the air moleculesvia vibration. The sound waves reach thelistener from the source in this manner.The sound wave simply impinges upon afunnel (the pinna) in the human ear,which acts to feed the sound wave downa natural tube (the ear canal) to aterminating membrane (Jympanicmembrane) to make it vibrate inresponse to the sound pressure variationand hence ‘pass on’ the sound energyvia mechanical vibration. The soundwave is enhanced on arrival at the eardrum. This is a result of head baffle andear cancel resonance. Figure 2 showsdifferent regions of the pasilar

Fig. 2: The Basilar Membrane of the Human Cochlea

41H E A R I N G — APHYSICAL PHENOMENON

membrane of the ear that are sensitiveto different range of frequencies.

If a person is to perceive a stimulus,it will be necessary to translate themolecular sound energy to fluid vibratoryenergy in the cochlea, which will in turnproduce the electrical potentials of theauditory nerve fibres. This can beachieved effectively in human by meansof conducive pathway of the ear, whichfacilitates the efficient transfer ofacoustic vibratory energy into fluidvibratory energy, with the resultantgeneration of electrical potentials in theauditory nerve (Fig. 3).

of sound energy transfer from tympanicmembrane to stapes foot plate beingachieved via mechanical vibration of theear ossicles. The sound pressure at thestapes foot plate is therefore enhancedby a factor of ~18 relative to that at thetympanum membrane.

The ossicles may be considered as aseries of levers. Since the length of themanubrium and nech of the malleus islonger than the long process of the incus,a mechanical advantage of 1.3 results.Overall boost to sound pressure at thestapes foot plate is approximately a factorof 23 (i.e. 18 × 1.3).

Air molecules are very light, inelasticparticles while the perilymph moleculesare much denser and highly elastic. It isnecessary to boost the incoming soundwave, so that an effective transfer ofenergy to the fluid medium is achieved.The sound pressure at the tympanicmembrane is enhanced to that at theentrance to the pinna by the resonanceeffects of cochlea and ear canal. Thissound pressure acts upon the tympanicmembrane and causes vibration. Two-thirds of membrane area is involved insound pressure transfer to themanubrium of the mallius — a passage

Sound wave[about 100 Hz]

Action Potentialsfrom oneauditory neuron

Fig. 3

The inner ear consists largely ofthe cochlea a fluid filled coiled-tunnelthat contains the receptors for hearing.The basilar membrane, which runs theentire length of the spiraled cochlea,holds the authority receptors called haircells.

Vibrations that are transmitted tocochlea through the oval window by thefoot plate of the stapes set up vibrationsin the perilymph which surrounds themembranous labyrinth containing theend organs of hearing and balance. Atlast the vibration of the basilarmembrane cause a pull or shearing force

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on the hair cells attached to the tectorialmembrane. This action transform thefluid vibratory energy into electricalimpulses that stimulate the fibres of theacoustic nerve (eighth cranial nerve).

These signals then travel along theacoustic nerve to the brain where theyare translated into sound, whether it isthe sound of rustling leaves or chirpingbirds or cars backfiring.

REFERENCES

SAIHGAL, B.L. A textbook of Sound.TUCKER, IVAN AND NOLAN, MICHAEL, Educational Audiology.WEITEN, WAYNE. Psychology Themes and Variation.

43NANOSCIENCE AND NANOTECHNOLOGY:PERSPECTIVES AND OVERVIEW

Nanoscience andNanotechnology:Perspectives and Overview

R. RAVICHANDRAN

Regional Institute of Education (NCERT)Bhopal 462 013

P. SASIKALA

Makhanlal Chaturvedi NationalUniversity, 222 Zone-I, MP NagarBhopal 462 011

ANOSCIENCE is fast becoming one ofthe major areas of science. Itsappeal lies in the long-dreamt-of

ability to investigate and manipulatematter at the level of individual atomsand molecules. And while it is scientificcuriosity that is currently drivingresearch forward in this area, there isthe tempting thought that discoveriescould play key role in a future world ofnano-devices and nano-computers.Hence, it becomes very much essentialon the part of the science teachers to getthe science students exposed, enrichedand motivated on this interdisciplinaryfield which is going to rule this knowledgesociety. Also efforts should be made toinclude this thrust area in schoolscience curriculum appropriately, for asuccessful exploitation of this upcomingarea.

Introduction to Nanotechnology

Nanotechnology is defined as fabricationof devices with atomic or molecular scaleprecision. Devices with minimum featuresizes less than 100 nanometres (nm) are

considered to be products ofnanotechnology. A nanometre is onebillionth of a metre (10-9 m) and is theunit of length that is generally mostappropriate for describing the size ofsingle molecules. The nanoscale marksthe nebulous boundary between theclassical and quantum mechanicalworlds; thus, realisation of nano-technology promises to bringrevolutionary capabilities. Fabrication ofnanomachines, nanoelectronics andother nanodevices will undoubtedly solvean enormous amount of the problemsfaced by mankind today.

Nanotechnology is currently in avery infantile stage. However, we nowhave the ability to organise matter on theatomic scale and there are alreadynumerous products available as a directresult of our rapidly increasing ability tofabricate and characterise feature sizesless than 100 nm. Mirrors that don’t fog,biomimetic paint with a contact anglenear 180o, gene chips and fat solublevitamins in aqueous beverages are someof the first manifestations ofnanotechnology. However, immenantbreakthroughs in computer science andmedicine will be where the real potentialof nanotechnology will first be achieved.

Nanoscience is an interdisciplinaryfield that seeks to bring about maturenanotechnology. Focusing on thenanoscale intersection of fields such asphysics, biology, engineering, chemistry,computer science and more, nanoscienceis rapidly expanding. Nanotechnologycentres are popping up around the worldas more funding is provided andnanotechnology market share increases.The rapid progress is apparent by the

N

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increasing appearance of the prefix“nano” in scientific journals and thenews. Thus, as we increase our abilityto fabricate computer chips with smallerfeatures and improve our ability to curedisease at the molecular level,nanotechnology is here.

A Brief History of Nanotechnology

The amount of space available to us forinformation storage (or other uses) isenormous. As first described in a lecturetitled, ‘There’s Plenty of Room at theBottom’ in 1959 by Richard P. Feynman,there is nothing besides our clumsy sizethat keeps us from using this space. Inhis time, it was not possible for us tomanipulate single atoms or moleculesbecause they were far too small for ourtools. Thus, his speech was completelytheoretical and seemingly fantastic. Hedescribed how the laws of physics do notlimit our ability to manipulate singleatoms and molecules. Instead, it was ourlack of the appropriate methods for doingso. However, he correctly predicted thatthe time would come in which atomicallyprecise manipulation of matter wouldinevitably arrive.

Prof. Feynman described such atomicscale fabrication as a ‘bottom-up’approach, as opposed to the ‘top-down’approach that we are accustomed to. Thecurrent top-down method formanufacturing involves the constructionof parts through methods such ascutting, carving and molding. Usingthese methods, we have been able tofabricate a remarkable variety ofmachinery and electronics devices.However, the sizes at which we can make

these devices is severely limited by ourability to cut, carve and mold.

Bottom-up manufacturing, on theother hand, would provide componentsmade of single molecules, which are heldtogether by covalent forces that are farstronger than the forces that holdtogether macro-scale components.Furthermore, the amount of informationthat could be stored in devices built fromthe bottom-up would be enormous.

Since that initial preview ofnanotechnology, we have developedseveral methods which prove thatProf. Feynman was correct in hisprophesy. The most notable methods are‘scanning probe microscopy’ and thecorresponding advancements in‘supramolecular chemistry’. Scanningprobe microscopy gives us the ability toposition single atoms and/or moleculesin the desired place exactly as Prof.Feynman had predicted. Although thelimitations of traditional chemistry werecriticised in Prof. Feynman’s lecture dueto its seemingly tedious and randomnature, recent advancements haveimproved its potential uses fornanotechnology.

Why Make Nanotechnology?

One might ask, ‘what exactly are thepotential uses of nanotechnology?’ In thelimited number of years thatnanotechnology has been consideredpossible, a plethora of answers to thisquestion have been presented. Possibleanswers include quantum computers,long term life preservation and virtuallyeverything in between. It seems thatnanotechnology could potentially solve

45NANOSCIENCE AND NANOTECHNOLOGY:PERSPECTIVES AND OVERVIEW

just about any problem that we couldthink of; thus, a more interestingquestion is, ‘what real problems willnanotechnology solve first?’ As of now, itappears that the first revolutionaryapplications of nanotechnology will be incomputer science and medicine. Thesetwo fields will most likely be affected firstsince they both call for molecular scalemanipulation of matter in the nearfuture.

Nanomaterials. Nanodevices andApplications of Nanomaterials

Nanomaterials are single-phase or multi-phase polycrystals with a typicalcrystal size of 1 to 100 nm in at leastone dimension. Depending on thedimensions they can be classified into(a) nanoparticles; (b) layered or lamellarstructures; (c) filamentary structures;and (d) bulk nanostructured materials.The properties of nanomaterials mainlydepend on four features, namely (a) grainsize and size distribution; (b) chemicalcomposition; (c) presence of interfaces(grain boundaries, free surface); and (d)interactions between the constituentdomains. Due to the large surface/interface to volume ratio in nanophasematerials, a wide variety of size-relatedeffects can be introduced by controllingthe size of the particles:

● The density of dislocation, interfaceto volume ratio and the grain sizestrongly influence the mechanicalproperties.

● Quantum confinement, i.e.,quantisation of the energy levels ofthe electrons due to confined grain

size, has applications insemiconductors, optoelectronics,and nonlinear optics. Nanoclusters,so-called quantum dots for examplecan be developed to emit and absorba specific wavelength of light bychanging the particle diameters.

● The large amount of surface atomsincreases the activity for catalyticalapplications.

● The magnetic properties of nano-sized particles depend on the largesurface to volume ratio. Unlike bulkmaterials consisting usually ofmultiple magnetic domains, severalsmall ferromagnetic particles canform only a single magnetic domain,giving rise to superparamagnetism.This behaviour opens the possibilityfor applications in informationstorage.

Nanodevices may be defined asstructurally organised and functionallyintegrated chemical systems in thedimension of nanometres. Thecomponents may be photo-, electro-,iono-, magneto-, thermo-, mechano-, orchemoactive, depending on whether theyhandle photons, electrons, or ions,respond to magnetic fields or to heat,undergo changes in mechanicalproperties, or perform a chemicalreaction.

Areas of application that can beforeseen to benefit from the small size andorganisation of nanoscale objects includequantum electronics, nonlinear optics,photonics, chemoselective sensing, andinformation storage and processing,adsorbents, catalysis, solar cells,

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magnetic recording devices, superplasticceramics, superhard metals, metastablealloys.

Semiconductor Fabrication

Moore’s law, optical lithography and thesearch for alternatives

Computer chips (and the silicon basedtransistors within them) are rapidlyshrinking according to a predictableformula (by a factor of 4 every 3 years –Moore’s Law). According to theSemiconductor Industry Association’sextrapolation of formulas such as this one(SIA road map) it is expected that thesizes of circuits within our chips willreach the size of only a few atoms inabout 20 years.

Since almost all of our moderncomputers are made from silicon‘semiconductor’ transistors patternedand carved by light (photolithography),the shrinking of circuits predicted by theSIA may not be the most economicalmethod for the future. An enormousamount of money has been invested inthe semiconductor industry in order toconsistently shrink and improve oursemiconductor electronics. Smallercircuits require less energy, operate morequickly and, of course, take up lessspace. Thus, Moore’s law has beenadhered to since computers first becamecommercially available. However, thissimple shrinking of components can notcontinue for much longer.

As transistors such as the Metal-Oxide Semiconductor Field EffectTransistor (MOSFET - one of the primarycomponents used in integrated circuits)is made smaller, both its properties and

manufacturing expense change with thescale. Currently, Ultraviolet light is usedto create the silicon circuits with a lateralresolution around 200 nm (thewavelength of ultraviolet light). As thecircuits shrink below 100 nm newfabrication methods must be created,resulting in increasing costs.Furthermore, once the circuit sizereaches only a few nanometres,quantum effects such as tunneling beginto become important, which drasticallychanges the ability for the computers tofunction normally. Thus, novel methodsfor computer chip fabrication have beenand are being intensely sought bymicrochip manufacturers.

Molecular and Quantum Computing

Alternative architectures fornanocomputing

In addition to single electron transistors,two promising alternatives to traditionalcomputers are molecular computing andquantum computing. These two methodsare intimately related, yet deal withinformation on two different levels. Muchprogress has been made in these areasduring the last few years and both havebeen shown to be feasible replacementsfor semiconductor chips.Quantum computing seeks to write,process and read information on thequantum level. It is at the nanoscalethat quantum mechanical effects suchas (the wave particle duality) begin tobecome apparent. Numerous scientistsare seeking ways to store informationwithin the ‘quantum mechanical’ realm.This is not a simple task because of thedelicate nature of quantum mechanical

47NANOSCIENCE AND NANOTECHNOLOGY:PERSPECTIVES AND OVERVIEW

systems. However, since the laws ofquantum mechanics involvesunintuitive principles such assuperposition and entanglement, aquantum computer would be able toviolate some rules that limit our classicalcomputers. For instance, takingadvantage of superposition would meanthat a quantum bit of information,termed a ‘qubit’ would be able to be usedin several computations at the sametime. Taking advantage of entanglementwould mean that the information couldbe processed over ‘long distances’without the classical requirement ofwires.Molecular computation is another methodcomplimentary to quantum computingthat seeks to write, process and readinformation within single molecules. Onemolecule that has proved most promisingfor molecular computation isDeoxyribonucleic acid (DNA). DNA is along polymer made of 4 differentnucleotides that can be represented bythe letters A, T, C and G. The order orsequence of these nucleotides withinDNA provides the information for makingprotein, the main components of themolecular scale machinery used by livingorganisms to carry out life sustainingfunctions.

Mathematicians have figured outnumerous ways to use DNA as thevarious proteins that come with it tocarry out numerical computations thatare notoriously difficult for siliconcomputers, namely ‘NP-complete’problems. The advantage that molecularcomputing using DNA has overconventional computing is that it is

massively parallel. This means that eachDNA molecule can function as a singleprocessor, which greatly improves thespeed of computation for complexproblems.

Medical Applications

Molecular medicine, bioinformatics andbiomolecular nanotechnology are rapidlyincreasing our ability to heal and stayhealthy

The other field in which molecular scalemanipulation of matter is receivingabundant attention is medicine. Sinceall living organisms are composed ofmolecules, molecular biology has becomethe primary focus of biotechnology.Countless diseases have been cured byour ability to synthesise small moleculescommonly known as ‘drugs’ that interactwith the protein molecules that make upthe molecular machinery that keeps usalive. Our understanding of how proteinsinteract with DNA, phospholipids andother biological molecules is what allowssuch progress.

Living systems are able to livebecause of the vast amount of highlyordered molecular machinery fromwhich they are built. The central dogmaof molecular biology states that theinformation required to build a living cellor organism is stored in the DNA (whichwas described above for its use inmolecular computation). This informationis transferred from “M the DNA to theproteins by the processes called‘transcription’ and ‘translation’. Theseprocesses are all executed by variousbiomolecular components, mostly proteinand nucleic acids.

48SCHOOLSCIENCE

June2006

Molecular biology is a field in whichthe study of these interactions has ledto the discovery of numerouspharmaceuticals that have beenenormously effective in curing disease.Understanding of molecularmechanisms, including substraterecognition, energy expenditure, electrontransport, membrane activity and muchmore have greatly improved our medicaltechnology.

So, what does this have to do withnanotechnology? First of all it shows theabilities of molecular scale machinery.Since the goal of nanotechnology ismolecular and atomic precision,nanotechnology has much (if noteverything) to learn from nature.Copying, borrowing and learning tricksfrom nature is one of the primarytechniques used by nanotechnology andhas been termed ‘biomimetics’. Secondly,our ability to design synthetic, semi-synthetic and natural molecularmachinery gives us an enormouspotential for curing disease andpreserving life. An extensive textbooktitled ‘Nanomedicine’ has been writtenand does an excellent job of summarisinghow nanotechnology is changingmedicine.

Molecular Simulation

Computer models of atoms, moleculesand nanostructures provide the theorybehind nanoscience

Finally, a branch of computer sciencethat is allowing rapid progress to bemade in nanotechnology is the computersimulation of molecular scale events.Molecular simulation is able to provide

and predict data about molecularsystems that would normally requireenormous effort to obtain physically. Byorganising virtual atoms in a molecularsimulation environment, one caneffectively model nanoscale systems.Deepak Srivastava, one of the world’sleading experts in molecular simulationand computational nanotechnology, hasdescribed the situation with the followingquote, Theory, modeling and simulationshave provided and will continue to provideinsights into what to expect next andverification/explanation of what has beendone or observed experimentally. Fornanoscale systems, simulations andtheory in fact have provided novelproperties that has led to new designs,materials and systems for nanotechnologyapplications. For example carbonnanotubes applications in molecularelectronics or computers were predictedfirst by theory and simulations, theexperiments are now following up tofabricate and conceptualise new devicesbased on those simulations.

Current limitations of molecularsimulation techniques are the molecularsimulation algorithm and computationtime for complex systems. Force fieldalgorithms are currently quite efficientand are often used today. However, suchmodels neglect electronic properties ofthe system. In order to calculate electrondensity, quantum mechanical modelsare required. However, as the number ofatoms and electrons is increased, thecomputational complexity of the modelquickly reaches the limits of our mostmodern supercomputers. Thus, as thecomputational abilities of our computersare improved (often with help from

49NANOSCIENCE AND NANOTECHNOLOGY:PERSPECTIVES AND OVERVIEW

nanoscience), increasingly complexsystems will be within the reach ofmolecular simulation.

The Future

Nanotechnology has arrived, but it hasyet to realise its full potential

Our computers are quite fast and small,but no revolutionary breakthrough incomputing has happened since thetransistor was invented. The humangenome project has reached completion,yet limits in our ability to cure diseaseon a molecular basis remain. While it isoften difficult to predict the future, somethings seem inevitable. Just as a ballthrown into the air can be expected tofall to the ground, so can we expect ourtechnology to reach the molecular scale.We must keep a very close pace with thisnew technology to harvest the best

potentials at the right time or else we willperish.

Useful links on the NET

www.nano.ku.dk/research/nanochemistry/www.nanoindustries.comwww.cordis.lu/nanotechnology/www.nanonet.dewww.ieee.org/portal/indexwww.nanotechweb.orghttp://home.pusan.ac.kr/~nanobio//http://nano.gov/www.nanoapex. comwww.nd.edu/~ndnano/index.htmlwww.nanobio.comwww.nsti.org/www.nanobionet.de/www.nanoword.net/pages/quiz.htmwww.mitre.org/tech/nanotech/www.nanoword.net/pages/busquiz.ht

REFERENCES

SMALLEY, R.E. 1999. Nanotechnology — A Revolution in the Making — Visionfor R&D in the Next Decade, Interagency Working Group on Nanoscience,Engineering, and Technology, USA.

GONSALVES, K.E., RANGARAJAN, S.P., WANG, J. 2000. Handbook of NanostructuredMaterials and Nanotechnology, Vol. I, Synthesis and Processing, AcademicPress.

Srinivasan, S. 2004. Nanotechnology: the next revolution, National Book Trust,New Delhi.

MHRD, Govt. of India. 2004. Nanoscience & technology base and vision forR&D in India, New Delhi.

50SCHOOLSCIENCE

June2006

An Investigation into theLearning DifficultiesExperienced by IndianSchool Children InLearning DivisionAlgorithm of SimpleFractions

TAPAN KUMAR MAITI

Assistant TeacherHetia High School (H. S.)

JAYANTA KUMAR METE

Reader, Department of EducationUniversity of KalyaniNadia, West Bengal 741 235

HE ONLY division algorithm forsimple fractions which is beingtaught to the school children is

the reciprocal algorithm. Apparently it isvery simple. But, taught mechanically,it gives rise to many learning difficulties,which the present investigation intendsto highlight for the benefit of students,teachers and method masters.

Introduction

After the introduction of cheap hand-held calculating machines, use ofdecimal fractions in daily life has becomevery convenient. The teaching-learningof decimal fractions has also undergonea sea change.

But matters have not been so muchfortunate in case of public use orteaching-learning of simple fractions (alsocalled “common” or “vulgar” fractions),

though they have been as useful asbefore. There is no mechanical device tofacilitate the use of such fractions. Theteaching-learning of the algorithms ofsimple fractions has remained the samefor decades.

Under these circumstances, the onlyways to ameliorate the teaching-learningof simple fractions are to select themethods of operation for them mostjudiciously, and to follow up theirteaching-learning with diagnosticprogrammes and remedial measures.

The Only Division Algorithm forSimple Fractions taught in Schools

Now there is one division algorithm forsimple fractions that is used in theschools for teaching the school children.It is the reciprocal algorithm. Its rule isas follows:

To divide a number by a fractionmultiply the number by the reciprocal ofthe fraction.

(The reciprocal of a fraction is thefraction formed by interchanging thenumerator and denominator; for

example, the reciprocal of )cd

isdc

.

Thus, in this method:

cd

ba

dc

ba

×=÷

The rationale of the method is asfollows.

a c a d c d a d a d

1 .b d b c d c b c b c

So we see that, in this method, the

divisor is reduced to unity by multiplyingit by its reciprocal fraction. To keep

T

51AN INVESTIGATION INTO THELEARNING DIFFICULTIES EXPERIENCED...

balance, the dividend is also multipliedby reciprocal of the divisor.

The major criticism of this method isthat the teachers often forget to tell thestudents the mystery behind theinversion of the divisor, and then its useas the multiplier of the dividend to getthe quotient.

Previous Researches on SimpleFractions

From a study of recent researches onsimple fractions, it was found that thealgorithms of simple fractions had notdrawn the attention of investigatorsduring the last 25 years. In 1930,Brueckner administered his ‘DiagnosticTest in Fractions’ to 400 sixth gradeBritish pupils and made an analysis ofthe most frequent types of errors [Blair1962, 231-234]. In 1979 Smithexperimentally compared two methods(techniques) of division of fractions,namely, ‘The common denominatormethod’ and the ‘Reciprocal Method’(also called the ‘Method of Inversion’) ontheir related gain in pupil achievement.The reciprocal was found by him superiorto the common denominator method andis significantly increasing pupils’achievement in division of simplefractions [vide C. A. Smith, ‘Effect of aMeaningful treatment for Division ofFractions a Comparative Study’(unpublished Doctoral Dissertation, theUniversity of Texas at Austin, 1979). InIndia, in 1980 A. Bhattacharyaconducted a doctoral study ‘to diagnoseand prevent the learning disabilities ofIndian primary school students in simpleand decimal fractions’ [unpublished

Doctoral Dissertation, University ofCalcutta, 1980].

Need of Diagnostic Programmes

Faulty teaching-learning of the basicmathematical skills may lead todevelopment of learning difficulties in astudent. Uncorrected for long, thelearning difficulties may develop intopermanent-learning disabilities whichmay impede the learning of mathematicsand career of the concerned student.

Hence diagnostic testing after thetesting-learning of basic mathematicalskills should be an integral part of aschool programme. The data can help asincere teacher to help the concernedstudents individually to ameliorate theirlearning. It would also help the teacherto formulate his/her teaching strategiesso that the learning difficulties may notoccur in his/her students in future

Need of the Study

Thus, the only work, investigators ofpresent study, known to in the last 25years that had considered Indianstudents’ learning difficulties in simplefractions, was that of A. Bhattacharya(1980). It is unfortunate that theinvestigator paid little attention todivision of simple fractions, probablythinking that it was only a modifiedversion of fraction multiplication, whichthe ‘Reciprocal’ or ‘Inversion’ Method ofdivision of fractions appears to be tomany.

But experts like Brueckner [Ibid],Siddons [Godfrey and Siddons 1957, 123-124], Mueller [Mueller 1964,251-252],Adams, Ellis and Beeson [Adams, Ellis,

52SCHOOLSCIENCE

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and Beeson 1977, 138] and many othershave pointed out that, thoughapparently the reciprocal algorithm fordivision of fractions is very easy to useand practise, it is the major source oflearning difficulties faced by the schoolstudents in doing division of fractionssums in arithmetic.

This is why the investigators tookupon themselves the task of finding out,for the first time ever, the learningdifficulties of the Indian pupils in solvingdivision sums by the application of thereciprocal algorithm of simple fractions.

The Diagnostic Test used in the Study

“Brueckner Diagnostic Test in Divisionof Fractions” was published by theEducational Test Bureau, Minneapolis,Minnesota in 1930, 1943. The Test (videTable) attempts to determine in a verythorough manner what mistakes pupilsmake and why they make them. Itcontains 40 types of division sums. Adiagnostic tabulation sheet provided forit assists the teacher in interpreting thedata and in outlining suitable remedialwork. It had been used in the study toanalyse students’ difficulties in using thereciprocal method of division of fractions(vide Table).

Purpose of the Study

One of the investigators of the presentstudy is a practising school teacher, theother a methods master. Both wanted toknow the learning difficulties likely to bedeveloped by Indian school students inthe teaching-learning of the divisionalgorithm for simple fractions. But theyfound no such recent study conducted

on Indian school students. Theknowledge was important for both ofthem, because the school teacher hadto chalk out his teaching strategies inorder to prevent development of learningdifficulties amongst his pupils. And themethods teacher had to instruct thetrainees in this matter.

Selection of the Experimental School

The investigators were in favour of aschool in between low-achieving andhigh-achieving schools in which thestudents had been taught division offractions in a rather casual andmechanical manner. Such a schoolusually contains all types of students.They found a school in the BankuraDistrict which fulfilled all theserequirements, and, besides, it was a largeschool, with near about 200 students inClass VI. It was selected as theexperimental school, as its students wereexpected to show all learning disabilitiesarising out of faulty learning-teaching ofdivision of fractions.

The other details about theexperimental school are as follows:Type of school: Higher Secondary withArts and Commerce streams.Number of students (average of last threeyears) : 1400 students.Nature of location : Rural.General academic qualifications ofguardians: Very few are graduates orhave higher qualifications.

The Sample

The sample for the study consisted of 101students of Class VI selected randomlyfrom 185 students of the class. They had

53AN INVESTIGATION INTO THELEARNING DIFFICULTIES EXPERIENCED...

been taught the reciprocal method ofdivision of fractions “by rote”, by beingmade to use the method onlymechanically, without having anyexplanation of the inversion of the divisorand then its use as the multiplier.Actually it was this ignorance of thestudents for which the investigators hadselected their class, as they were likelyto display all possible learning errors forIndian students who are victims of faultyteaching of the reciprocal method.

Of the 101 students, 45 were boysand 56 girls. Their average age was 12years. As the IQs of the students wereunavoidable, their average score in thelast Half yearly examination of 281 marksand their average score in the lastArithmetic Test in the last Half yearlyexamination of 28 marks were obtainedinstead, as the correlation betweenscholastic aptitude and academicachievement is very high.

Administration of the Diagnostic Test

The test was administered on thesubjects on 23.10.02 (Wednesday) in twosittings. The first sitting was held from1.10 to 1.50 p.m., and the second, afterthe tiffin recess, from 2.20 to 2.55 p.m.One of the investigators supervised thetestings.

Results

The following Table presents the obtaineddata grouped under possible categoriesof learning difficulties. The analysis inthe Table is based entirely upon anexamination of the pupils’ answer sheetsafter they had been tested in a group.Consequently, the cause of some of the

errors which were found could not beascertained. This is shown in 2(c) and10 of the Table under the caption“unknown”. Nonetheless, the analysiswould provide the teacher with a list ofthe major mistakes pupils make indealing with problems on fractions.Individual diagnosis would reveal theunknown sources of error.

Findings of the Study

Following were the findings of thediagnostic study:1. 31.70 per cent (that is,

approximately one third) of allmistakes in division of fractions weredue to the student’s negligence toinvert the divisor before performingthe process of multiplication.

2. 24.70 per cent of all mistakes indivision of fractions were due to thestudent’s lack of comprehension ofthe process involved.

These support Mueller’s observationthat the “why” behind the reciprocalmethod is not widely or easily understoodwhich accounts for the computationalblunders [Mueller 1964, 251]. Here themisunderstanding reached the peak [(1)+ (2) make up for 56.40 per cent of totalerrors made by the pupils] because thestudents had not been explained thelogic behind the reciprocal method andwere asked to use it mechanicallywithout asking for the “why” of it. That iswhy the students inverted the dividendin place of the divisor (9.82 per cent oftotal errors were due to it), or invertedboth dividend and divisor (13.82 per centof total errors were due to it), so that“inverting” the wrong term accounted for

54SCHOOLSCIENCE

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Table 1: Analysis of Difficulties in Division of Fractions

Different Types of Errors Number of Per-Errors centage

1. Wrong operation: Multiplication: 565 31.70

247

22455

35

811

32

183

1 ==×=⎟⎠

⎞⎜⎝

⎛ ÷

2. Computation Errors

(a) Division: 1413

1427

74

827

43

183

3 ==×=÷ 3

(b) Multiplication: 52

or3012

72

56

21

381

1 ==×=÷ 54

(c) Unknown: 211

3or2140

74

310

43

131

3 ==×=÷ 20

77 4.323. Lack of Comprehension of process involved

(a) Inverts dividend: 1211

2or1235

27

65

21

351

1 ==×=÷ 175

(b) Inverts both dividend and divisor:

5524

53

118

32

183

1 =×=÷ 246

(c) Adds denominators and multiplies numerators:

137

2or1333

53

811

32

183

1 =×=÷ 1

(d) Adds numerators and multiplies denominators:

358

72

56

21

351

1 =×=÷ 2

(e) Disregards denominator in quotient:

554

825

41

181

3 =×=÷ 5

(f) Disregards numerator: 313

91

31

91

=×=÷ 11

440 24.70

55AN INVESTIGATION INTO THELEARNING DIFFICULTIES EXPERIENCED...

4. Difficulty in Reducing Fractions to thelowest terms

(a) Does not reduce: 104

103

34

31

331

1 =×=÷ 57

(b) Divides denominator by numerator:

337

14033

53

811

32

183

1 ==×=÷ –

57 3.205. Difficulty in changing mixed numbers to

improper fractions:

91

11820

124

310

43

131

3 ==×=÷ 84 4.71

6. Omitted 10 0.57

7. Failure to reduce improper fractions to

mixed numbers:

25

54

825

41

181

3 =×=÷ 201 11.27

8. Errors in copying: 21

7or2

1513

25

31

41

1 =×=÷ 174 9.76

9. Cancellation Difficulties:

(a) Cancels within the denominators:

65

41

65

465

=×=÷ 3

(b) Cancels within the numerators:

353

73

56

21

351

1 =×=÷ 9

10. Unknown: 51

31

331

1 =÷ 12 0.67

162 9.10

1782 100.00

Notes: 70.311001782565

××

56SCHOOLSCIENCE

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23.64 per cent of total errors committed.As stated, non-inversion accounted for24.70 per cent errors. The similarity ofthe findings of the two diagnostic testingsheld 75 years apart upon children of twodifferent nations cannot escape ournotice.

One of the testings was Brueckner’sheld in 1930 upon 400 British schoolchildren. The other was by theinvestigators’ held in 2002 upon 101Indian school children of the same gradeand age group. In both the groups ofchildren, nearly one-third missed toinvert the divisor before using it as themultiplier of the dividend. But there werealso dissimilarities in findings. Whereas13.8 per cent of the British pupilscommitted computation errors, it wasonly 4.32 per cent in case of the Indianpupils, on the other hand, while 12.1 percent of the British pupils committederrors for “Lack of Comprehension of theprocess involved”, the figure was double(24.70 per cent) for the Indian pupils.

Suggestions for Prevention ofLearning Difficulties

Godfrey and Siddons think that the ruleof the reciprocal method of division offractions, viz., “Turn the divisor upsidedown and multiply by that” is quiteunnecessary and certainly dangerous forthe beginners. Instead of beginning withthe method, Siddons has suggested thefollowing method to start with [Godfreyand Siddons 1957, 123-124]. “If the

children are clear that 5 ÷ 8 = 85

,

it is natural to assume that 5

24

3

52

43

=÷

“This fraction has four “stories” andwe only want two. Obviously we shouldimprove matters by multiplying top andbottom by 4 and also 5.

87

18

154253

5452

5443

52

43

52

43

==××

=××

××==÷∴ .

Siddons expects that (see above)many pupils will discover the “reciprocalmethod” herefrom.

Siddons has also pointed out twoother benefits (other than preventing thedevelopment of learning difficulties in thedivision of fractions) of the treatmentsuggested by him [Ibid, 124] :

1. “In the treatment I have suggested;the whole argument is made to hangon the one rule, ‘the golden ruleabout fractions’ —

‘The value of a fraction is unalteredby multiplying (or dividing)numerator and denominator by thesame number.’

2. Exactly the same principles areused when dealing with fractions inalgebra.”

The investigators however are of theopinion that, as the reciprocal methodis the easiest division algorithm offractions, it will be desirable if it is taughtand learned with proper understandingof its logic. So the beginner will work outthe whole process as the following workedout problem, and will themselvesabbreviate the method.

Example 1 154

32÷ . The reciprocal of

415

is154

. Multiplied by it, the divisor will

57AN INVESTIGATION INTO THELEARNING DIFFICULTIES EXPERIENCED...

be reduced to unity. But to keep balance,the dividend will also be multiplied by

.4

15

.4

1532

14

1532

415

154

415

32

154

32

×=÷⎟⎠⎞

⎜⎝⎛ ×

=⎟⎠⎞

⎜⎝⎛ ×÷⎟

⎠⎞

⎜⎝⎛ ×=÷∴

Example 2

.165

58

1165

58

165

516

165

58

516

58

51

353

1

×=÷⎟⎠⎞

⎜⎝⎛ ×

=⎟⎠⎞

⎜⎝⎛ ×÷⎟

⎠⎞

⎜⎝⎛ ×=÷=÷

REFERENCES

ADAMS SAM, LESLIE ELLIS, BEESON, B.F. 1977. “Teaching Mathematics withemphasis on the Diagnostic Approach”. Harper and Row Publishers, NewYork. Hagerstown. San Francisco. London.

BHATTACHARYA, A. 1980. “Diagnosis and Prevention of the Learning Disabilitiesof Primary School students in Arithmetic”. Unpublished DoctoralDissertation, University of Calcutta.

BLAIR, GLENN MYERS. 1962. “Diagnostic and Remedial Teaching”. The MacmillanCompany. New York.

GODFREY, CHAIRES AND SIDDONS, A.W. 1957. “The Teaching of ElementaryMathematics”. Cambridge at the University Press.

MUELLER, FRANCIS J. 1964. “Arithmetic its Structure and Concepts”. Prentice-Hall Inc. Englewood Cliffs. N.J.

SMITH, C.A. 1979. “Effects of a Meaningful Treatment for Division of Fractions:A Comparative Study”. Unpublished Doctoral Dissertation, The Universityof Texas at Austin.

58SCHOOLSCIENCE

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On Composition of NaturalNumbers

M.N. BAPAT

Regional Institute of EducationMysore

R.K. SONWANE

Department of MathematicsGovt. P.G. College, Balaghat(Earlier Teacher Research Fellow, Dr.H.S. Gour VishwavidyalayaSagar 470 003)

ATURE MANIFESTS itself througha variety of things live, dead orin fossil forms and that too in

several numbers. Here by number wemean “that handy device which helps usto judge and feel the extent of itsmanifestation” .

The number has been the buildingblock of mathematics. The history ofcounting things by a set of numbers isquite old. Adding a least integer count‘one’ to its preceding number has lead tothe formation of the successive integral

numbers. Basically a number not onlygives an idea about the size of a physicalquantity but also presents by whatcombination it can be arrived at.

If we critically observe thecomposition (structure) of a number wemight take a step forward inunderstanding the nature’s intricacies.The questions like: Why there are acertain number of leaves, spots, bushesor veins in plants? Why there are acertain number of arms, legs, etc. to ananimal? What is the rationale for thenumber of branches to a natural species?And so on.

Here we will discuss how a number> 1 is built up? What combinations orcomponents can a number be arrived at?What is unique about the componentsof a number? What is the consequenceof some of the unique components? Andmay be similar other questions.

Number as a Sum of Numbers

Let us first consider a few naturalnumbers.

If we look at these combinationscarefully we see that as we move to

N

1* = 12 = 1 + 1

3* = 1+24 = 1+1+2 or 2+2

5 = 1+2+2 or 2+3 or 1+1+3 etc ..........6* = 1+2+3 or 2+4 or 3+3 etc ..........

7 = 2+3+4 or 3+4 or 2+5 etc ..........8 = 1+3+4 or 3+5 or 2+6 etc ..........

9 = 1+3+5 or 2+7 or 4+5 etc ..........10* = 1 + 2 + 3 + 4 or 3+7 or 4+6 etc.........

59ON COMPOSITION OFNATURAL NUMBERS

higher numbers we have severalcombinations of its formation. Nowobserve the numbers that areunderlined. It is clear that thesenumbers can be formed by combinationof independent numbers.

1* = 1

3* = 1+2

5* = 1+2+2 or 2+3

6* = 1+2+3

7 = 2+3+4 or 3+4 or 2+5

8 = 1+3+4 or 3+5 or 2+6

10* = 1+2+3+4

Further it is interesting to note thatthe starred (*) numbers are special inthat they can also be formed bysuccessive integers. If one asks aquestion like: What is the probability offormation of a number? Naturally theanswer would be: it is proportional to thenumber of ways it can be obtained. Henceif we want to correlate these numbers tocharacterise a nature’s manifestation wecan expect that the probabilities ofoccurrence of the different species mustbe as per their numeric abundance. Doesit happen? Let us examine.

According to simple mathematics thestarred number N (i.e. N*) can beobtained as a sum of natural numbersup to a number n. As it is related through

N* = (n12) (1 + n)Clearly the numbers span over the

interval 1 to n.Then if we encounter n varieties

their disposition can be N fold.

Number as a Partition of Numbers

Let us now examine a few successive

natural numbers formed by thecombination of two numbers only.

2 = 1 + 1

3 = 1+2

4 = 1 + 3, 2 + 2

5 = 1 + 4, 2 + 3

6 = 1 + 5, 2 + 4, 3 + 3

7 = 1 + 6, 2 + 5, 3 + 4

so on

We can notice that the partition ofnumber into two non-repetitive numberscan be obtained in (n/2) — 1 ways if n iseven and (n-l)/2 ways if n is odd.

However, according to the theory ofprobability more equitable distributionamong these would generally prevail innature.

Now let us resolve the numbers intothree components as

3 = 1+1+1

4 = 1+1+2

5 = 1 + 1 + 3, 1 + 2 + 2

6 = 1 + 2 + 3, 2 + 2 + 2

7 = 1 + 2 + 4, 2 + 2 + 3

8 = 1 + 2 + 5, 1 + 3 + 4

so on.

We find that there are several waysof doing so. But a partition into non-repetitive components is unique. It is wellestablished and also we have shown inthe theory of magic squares that it is thenon-repetitive numbers that form amagic sequence. Then should we suggestthat structures of many natural systemscould be understood on the basis of non-repetitive components? Let us see whatcan be the basis for it.

60SCHOOLSCIENCE

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Theoretically a partition for a decimalnumber system can be obtained from theexpression

(Xl + X2 + X3 + ..... + X9)n

where n represents the number ofpartitions intended and powers of xrepresents the number to be partitionedinto n components. The numbers of waysin which we get the desired power arethe proper partitions. Thus if we want topartition 15 in 3 components then thepower 15 of x is to be got from theequation

(X1 + X2 + X3 + ..... +X9)3

which is obtained as

X1+5+9, X1+6+8, X1+7+7, X2+4+9, X2+5+8,X3+3+9, X3+4+8, X4+2+9, X4+3+8, X4+4+7, X4+5+6,X5+5+5, etc.

If we identify among these partitionsthe partitions with non-repetitivenumbers we see that only 8 partitionsare unique. Incidentally as we have

indicated these are the combinationsthat occur when we want to form a magicsquare.

Nature is scrupulously selective. Itselects out probably unique combi-nations of the numbers in forming itsvariegated design for its animal andplant kingdom. Man is also takingadvantage of the nature’s selectivenature in his endeavours for hisdevelopmental activities.

One may claim that if the theoriesare properly coordinated we canunderstand why certain numbers arepreferred over the others in certainspecies of nature’s creation.

With the advances in science, it hasbeen claimed that a binary orhexadecimal system is to be preferredover the decimal number system. Letprogress choose its own way but itmay be remembered that by choosinga certain counting method thenature’s unique manifestation is notgoing to alter.

REFERENCES

BAPAT, M.N. AND SONWANE, R.K. 1996. Magic Squares. Science Reporter, p.19.DAVIS, P.J. 1961. The Lore of Large Numbers. The L.W. Singer Company.PATNAIK, R.K. 1994. Calculus. CBS Publishers and Distributors, New Delhi.

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India to explore the moon

India has announced that it plans toexplore the Moon and will send anunmanned probe there by 2008. TheIndian Space Research Organisation(ISRO) calls the first Moon Flight ProjectChandrayan Pratham, which has beentranslated as First Journey to the Moonor Moonshot One. The Chandrayan-1weighing nearly 525 kg would belaunched in 2007 or 2008 from one ofIndia’s own Polar Satellite LaunchVehicle (PSLV) space rockets.At first, the spacecraft would circle Earthin a Geosynchronous Transfer Orbit(GTO). From there, it would fly on outinto a polar orbit of the Moon some96 km above the lunar surface.The Chandrayan-1 mission would carryX-ray and gamma-ray spectrometersand would send back data that scientistson Earth would use to produce ahigh-resolution digital map of the lunarsurface. The project’s main objectivesare high-resolution photography of thelunar surface using remote-sensinginstruments sensitive to visible light,near-infrared light, and low-energy andhigh-energy X-rays. Space aboard thesatellite also will be available forinstruments from scientists in othercountries.

The European Space Agency (ESA)has agreed to support India’s plan tosend a probe to the Moon by providingthree science instruments forChandrayan-1. They will be identical to

those already in orbit around the Moonon ESA’s Smart 1 spacecraft, which issurveying chemical elements on thelunar surface. The Indian lunar satellitealso would carry with it a U.S. radarinstrument designed to locate water andice.

According to an ISRO press release,Chandrayan-1 is the first mission in“India’s foray into a planetary explorationera in the coming decades”.Chandrayan-1 will be the “forerunner ofmore ambitious planetary missions in theyears to come, including landing robotson the Moon and visits by Indianspacecraft to other planets in the SolarSystem.”

(Source: ISRO Press Release)

ISRO, NASA sign moon mission deal

Mr G Madhavan Nair, Chairman, ISRO,and Dr Michael Griffin, Administrator,National Aeronautics and SpaceAdministration (NASA) of U.S.A. on May9, 2006 signed Memoranda ofUnderstanding (MoU) at ISRO SatelliteCentre (ISAC), Bangalore. According toMoU two U.S. Scientific instrumentswould be included on board India’s firstmission to Moon, Chandrayan-1. Theseinstruments are: Mini SyntheticAperture Radar (Mini SAR) developed byApplied Physics Laboratory, JohnsHopkins University and funded by NASAand Moon Mineralogy Mapper (M3), jointlybuilt by Brown University and JetPropulsion Laboratory (JPL) of NASA.

Chandrayan-1, scheduled during2007-2008, is India’s first unmannedscientific mission to moon. The mainobjective is the investigation of the

Science News

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distribution of various minerals andchemical elements and high-resolutionthree-dimensional mapping of the entirelunar surface. ISRO’s Polar SatelliteLaunch Vehicle (PSLV), will launchChandrayan-1 into an earth orbit.Subsequently, the spacecraft’s ownpropulsion system would be used to placeit in a 100 km polar orbit around themoon.

The Indian payloads on boardChandrayan-1 include: a TerrainMapping Camera (TMC), a HyperSpectral Imager (HySI), a High-Energy X-ray spectrometer (HEX), a Lunar LaserRanging Instrument (LLRI) and a MoonImpact Probe (MIP).

The two US instruments, Mini SARand M3, were selected on the basis ofmerit out of 16 firm proposals from allover the world received in response toISRO’s announcement of opportunity.The main objective of Mini SAR is to detectwater in the permanently shadowed areasof lunar Polar Regions. The objective of M3

is the characterisation and mapping ofminerals on the lunar surface.

In addition to NASA instruments,three other instruments have alreadybeen selected by ISRO to be placed onboard Chandrayan-1 from the EuropeanSpace Agency. These are — Imaging X-Ray Spectrometer (CIXS) from RutherfordAppleton Laboratory, U.K., developedwith contribution from ISRO SatelliteCentre; Near Infra-Red Spectrometer(SIR-2) from Max Planck Institute,Germany; and Sub keV Atom ReflectingAnalyser (SARA) from Swedish Instituteof Space Physics developed incollaboration with ISRO’s VikramSarabhai Space Centre — besides a

RAdiation DOse Monitor (RADOM) fromthe Bulgarian Academy of Sciences.

The inclusion of US instruments onChandrayan-1 would further strengthenthe cooperation between India and USAin the field of space research which datesback to the very beginning of the Indianspace programme

(Source: ISRO Press Release)

First custom-made bladderstransplanted

According to a research report at leastseven patients had received newbladders that have been engineered froma plug of tissue grown from their own,dysfunctional bladders. Researchersclaimed that such custom-madebladders grown from patients’ own cellshave been successfully transplanted andwork, in some cases for years. Dr.Anthony Atala, Wake Forest Universityin North Carolina, and the leader of theresearch team opined that their researchhas shown that regenerative medicinetechniques can be used to generatefunctional bladders that are durable.Patients given transplants of bladdersmade from their own cells, unlike thosewho are given organs transplants fromeither living or dead donors, would notneed to take drugs to prevent organrejection.

The patients were children and teensaged 4 to 19 who had poor bladderfunction because of a congenital birthdefect that causes incomplete closure ofthe spine. According to Atala, a urinarysurgeon and an expert in regenerativeand stem cell science, their researchsuggests that regenerative medicine may

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one day be a solution to the shortage ofdonor organs for those needingtransplants.

Vitamin D and calcium may lowerdiabetes risk

Women with high intakes of Vitamin Dand calcium appear to have a lower riskof developing type 2 diabetes, accordingto a team of Boston-based researchersled by Dr. Anastassios G. Pittas, ofTufts-New England Medical Centre.Dr. Anastassios G. Pittas and hiscolleagues analysed the data collected on83,779 women having no history ofdiabetes, cardiovascular disease orcancer when they enrolled in the study.Vitamin D and calcium intake from foodsand from supplements were evaluatedevery 2 to 4 years. A total of 4843 newcases of diabetes were documented over20 years of follow-up.

According to researchers the latestguidelines set by the Institute of Medicineenvisage that only 3 per cent of womenin our cohort had adequate Vitamin Dintake, and only 24 per cent hadadequate calcium intake. Total VitaminD intake was not significantly associatedwith type 2 diabetes, but there was adifference when it came to Vitamin Dsupplements. The team saw a 13 percent lower risk of diabetes among womenin the highest versus the lowest categoryof Vitamin D intake from supplements.

Women with the highest totalcalcium intake had a 21 per cent lowerrisk of diabetes than those with thelowest intake. In this case, the source ofcalcium didn’t make much difference:the risk was 18 per cent lower among

women in the highest versus the lowestcategory of calcium intake fromsupplements. Overall, the lowest risk ofdiabetes was observed among womenwith the highest combined intakes ofcalcium and Vitamin D compared withthose with the lowest.

(Source: Diabetes Care)

Viruses ‘trained’ to build tiny batteries

Researchers trying to make tinymachines have turned to the power ofnature, engineering a virus to attractmetals and then using it to build minutewires for microscopic batteries. Theresulting nanowires can be used inminuscule lithium ion battery aselectrodes, which in turn would be usedto power very small machines.

An international team ofresearchers, led by a group at theMassachusetts Institute of Technology,used the M13 virus, a simple and easilymanipulated virus. They modified theM13 virus’ genes so that its outside layer,or coat, would bind with certain metalions. They then incubated the virus in acobalt chloride solution so that cobaltoxide crystals mineralised uniformlyalong its length.

Next a bit of gold was added to getthe desired electrical effects.Viruses cannot reproduce on their ownbut must be grown in cells, in this case,bacteria. Virus inject their geneticmaterial and then the cells pump outtheir copies. According to researchers,viruses ultimately form orderly layers.

The resulting nanowires worked aspositive electrodes for battery electrodes.The researchers hope to build batteries

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that range from the size of a grain of riceup to the size of existing hearing-aidbatteries. Each virus, and thus eachwire, is only six nanometres — sixbillionths of a metre — in diameter, and880 nanometres long. Earlier researchershave previously used viruses to assemblesemiconductor and magnetic nanowires.

Stem cells could boost strokerecovery

In rat studies, they also show promiseagainst cerebral palsy.

Researchers have claimed that they havesuccessfully reduced the effects of strokein rats by transplanting stem cells intothe rodents’ brains. According to themthe treatment also seemed to help ratsfight a condition similar to humancerebral palsy. However, as of now itcannot be guaranteed that the treatmentwill work in humans. According toCesario V. Borlongan, AssociateProfessor of Neurology at the MedicalCollege of Georgia in Augusta, a memberof the research team the tests in peoplecould begin as early as next year. Eventhen the treatment is not expected tototally cure stroke or cerebral palsy, still,it could help.

According to Borlongan, despitedecades of research, stroke remainsextremely common and very difficult totreat. Thousands of people suffer strokeseach day, but only few could access tonewer remedies such as tPA, a powerfulclot-busting drug. Cerebral palsy, adisabling neurological disorder ofchildhood, currently has no effectivetreatment.

However, because they have theability to transform themselves intovarious types of body cells, stem cellshave been thought to offer hope as ameans of regenerating diseased orinjured tissues. In fact, neuroscientistshave been experimenting with stem celltransplants in animals for several years,but with mixed results.

In the new study, Borlongan and hiscolleagues transplanted human bonemarrow cells into the brains of rats whohad suffered strokes. In their study, theresearchers avoided stem cells sourcedfrom embryos or foetuses, which is stillbeing debated on ethical and socialgrounds. Movement skills in the stroke-afflicted rats improved by 25 per cent afterstem cell treatment, according toBorlongan. The improvement came eventhough the treatment was given sevendays after a stroke. A 25 per centimprovement could translate intosignificant changes in how humanpatients get around. Bedridden patientsmay be able to use a wheelchair, andwheelchair-bound patients might moveup to a walker, he said. Researchersalso observed about a 25 per centimprovement in treated rats affectedwith a condition equivalent to humancerebral palsy. However, the researchersonly watched them for 14 days. Unlikethe rats in the stroke study, theserodents were injected with rat — nothuman — stem cells.

Beware of the telephone sets andcomputer keyboards!

Textbooks often teach us that most ofthe common infection — colds, flu,

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diarrhoea — are transmitted environ-mentally either through the air, water orpersonal contact including the surfaceswe touch. According to Charles Gerba, amicrobiologist and clean water expert atthe University of Arizona, people oftenunder -rate surfaces they come incontact at their place of work, at homeor other places they visit.

Experts believe that telephones,computer keyboards and sinks are morepotential sources of infection than thedoorknobs and elevator buttons. Basedon dozens of surveys conducted onbacteria and viruses in workplaces andhomes, Gerba asserts that people areusually cautious about the wrongthings. According to him chances thatdoorknobs could be potential sources ofinfection are usually low as they are notmoist. Therefore, one need not fear adoorknob too much.

Germs do not stick where peoplebelieve they will as has been revealed bya recent informal survey. An analysis ofthe survey data by Gerba illustrates howmicrobes take advantage ofmisconceptions to propagate themselves.Two computer keyboards, for example,were found to carry far more bacteriathan an elevator button, the handles andbutton on the communal microwave ovenor the office water fountain. Gerba warnsthat keyboards and telephones —especially when they are shared — areamong the most germ-laden places inhome or offices. Keyboards seem to belike a lunch table for germs as a lot ofstudies have revealed that on an averagethese harbour 400 times more bacteriathan the average toilet seat. The mainreason for such a dismal picture seems

to arise due to the fact that usuallynobody cleans the desktop. It is,therefore, perhaps not surprisingly, thatteachers have the highest exposure tobacteria and viruses, as has been foundby Gerba through his surveys.Accountants, bankers and doctors alsotend to have microbe-laden offices, whilelawyers came out surprisingly clean inthe germ-count stakes.

A technique is followed to have anoverall bacteria count for the generalsurveys. Swabs of each surface are sentto Gerba’s lab, where these bacteriacultures are done in a lab dish. Thegrowth of whatever bacteria are presentcan be used to estimate an overall loadof germs, including harmless E. colibacteria — which are found in the gutand are an indicator of what scientistsdelicately call “faecal contamination”.Some other bacteria usually present areKlebsiella pneumonia, Streptococcus,Salmonella and Staphylococcus aurous,some of which cause disease and someof which do not. And where there arebacteria, there can be viruses, whichcan stick onto a clean and dry surfacefor days and to a wet surface for weeks.

According to experts such knowledgemay be particularly useful as thepandemic of H5N1 avian influenza maybe a real threat in future. While the viruscurrently infects birds almostexclusively, experts say it shows thegreatest potential of any virus in decadesto cause a human pandemic. If it beginsto spread, basic hygiene would beessential to avoid infection.

Gerba notes that people tend not toknow where the most infectious placesare. For example, the bathrooms, toilet

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taps and their doors. Bathroom sinks,however, are another source of infectionas they are usually high in bacterialcounts because they have everythingbacteria like. It’s wet, it’s moist. In a homewe usually find more E. coli in a sink thana toilet. Usually, public urinals areusually the dirtiest. All taps, door andflush handles and even walls’ surfacesmay be laden with bacteria.

German scientists synthesise a newcompound

According to a research paper thatappeared in the Journal of BiologicalChemistry — an American Society forBiochemistry and Molecular Biologyjournal — Gunter Fischer and hiscolleagues at the Max-Planck ResearchUnit for Enzymology of Protein Folding inGermany have succeeded insynthesising a new compound thatdramatically decreases the damage toneurons in rats demonstrating strokesymptoms.

Brain strokes area is the leadingcause of death world over and also themost common cause of adult disability.An ischemic stroke occurs when acerebral vessel occludes, obstructingblood flow to a portion of the brain.Currently, there is only one approvedstroke therapy, tissue plasminogenactivator, which targets the thrombuswithin the blood vessel. Because of thelack of available stroke treatments,neuroprotective agents have alsogenerated as much interest asthrombolytic therapies.

The immuno suppressive drugFK506 (also known as Tacrolimus or

Prograf.) is often administered to patientsreceiving transplants to prevent organrejection. Derivatives of the drug are alsocommonly used in the treatment of autoimmune diseases. FK506 inhibits T-cellactivation by binding to members of theFK506-binding protein (FKBP) family.Interestingly, FK506, and severalmolecules with similar structures, alsodemonstrate neuroprotective andneuroregenerative effects in a wide rangeof animal models mimicking Parkinson’sdisease, dementia, stroke, and nervedamage.

Gunter Fischer and his colleagueshave now determined that neuroprotective FK506 derivatives specificallytarget a receptor called FKBP38.According to Fischer high FKBP38activity in neuronal cells triggermechanisms leading to programmed celldeath. Inhibition of FKBP38 make cellsmore predisposed to survive. Thescientists also synthesised a moleculethat specifically inhibits FKBP38 andadministered it to rats that wereexperiencing stroke symptoms. Fischerand his colleagues found that theircompound protected the rats’ neuronsand also caused neural stem cellproliferation and neuronal differen-tiation. Animals with symptoms ofdisabilities, similar to those due tostrokes, also showed improvement whenthey were given the synthetic drug. Theseresults suggest potential therapeuticapplication specific FKBP38 inhibitors inthe treatment of neuro degenerationfollowing stroke and a number of otherdiseases.(Source: http://www.asbmb.org)

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Triple discovery hints at extra-solarplanets

A team of astronomers had found threeenticing Neptune-sized planets orbitinga distant star. The three planets werefound after a two-year monitoring of thestar using a 3.6m telescope at theEuropean Southern Observatory (ESO)in La Silla, Chile. The discovery mayprove to be a further step towards thegoal of finding another Earth. More than170 planets outside our own Solar systemhave been spotted in the past decade orso. But almost all of them have beengaseous Jupiter-sized giants that movearound their star at a close range. Theiratmosphere would be too hot and toodense to have liquid water, an essentialingredient for life as we know it.

A team led by Christophe Lovis fromthe Geneva Observatory in Switzerlandlocated a smaller planetary systemorbiting the star HD 69830. The star is41 light years from Earth in the Puppisconstellation and is about four-fifths themass of our Sun. The three planets arequite large, being 10, 12 and 18 timeslarger in mass than the Earth. Thatmakes them about the size of ourNeptune, although a lot smaller thanJupiter, the biggest planet in our SolarSystem, and they appear to be solidplanets too, made of rock, not gas.

The two innermost planets areprobably so close to HD 69830 that theywould be blisteringly hot, but theoutermost one lies in what planet expertscall the “Goldilocks zone” — a comfortabledistance where water could exist as aliquid. Another discovery is that HD69830 also hosts, like our Sun, an

asteroid belt, the rubble left over from thebuilding of planets from dust and gassydebris that clump together throughgravitational attraction.

It may be too far fetched, accordingto researchers, to suggest that theseplanets contain life or the conditions forit, and it would be ludicrous anyway tothink of them as a potential home awayfrom home, given that our puny chemicalrockets and their passengers could neverreach there. But it shows that withpatient searching and the right tools,astronomers can uncover ever-smallerexoplanets in ever-wider orbits from theirstar, which may one day lead to findingcopies of Earth.

According to Michel Mayor, a memberof the research team who is also from theGeneva Observatory, the planetarysystem around HD 69830 clearlyrepresents a Rosetta stone in ourunderstanding of how planets form. Hewas referring to the stone that openedthe way to understanding thehieroglyphics of ancient Egypt. No doubtit will help us better understand thehuge diversity we have observed sincethe first extrasolar planet was found 11years ago, asserts Mayor.

(Source: NASA News)

A forward step in fusion research

A fusion reactor in which controlledfusion reaction could be made use toproduce huge amount of energy has beena long cherished dream of physicists. Ina fusion reactor, very high speedparticles are made to collide together toform a charged gas called a plasma. Thisplasma is contained inside a doughnut-

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shaped chamber called a tokamak bypowerful magnetic coils. In the variousdesigns of tokamaks developed so far indifferent parts of the world, none hasachieved a self-sustaining fusion eventfor longer than about five seconds, andthat too at a cost of using up far moreenergy than was yielded.

In 2005, a consortium of countrieshas signed a deal to build theInternational Thermonuclear Experi-mental Reactor (ITER) in southernFrance, which could serve as a test bedfor an eventual commercial design.However, experts associated withdesigning ITER are faced with manychallenges. One of them is a phenomenoncalled edge localised modes, or ELMs.These are sudden fluxes or eddy in theouter edge of the plasma that erode thetokamak’s inner wall — a highlyexpensive metal skin that absorbsneutrons emitted from the plasma.Erosion means that the wall has to bereplaced more often, which thus addshugely to costs. Eroded particles alsohave a big impact on the plasmaperformance, diminishing the amount ofenergy it can deliver.

Physicists working in the UnitedStates believe they have cracked theproblem facing man-made nuclearfusion, touted as the cheap, safe, cleanand almost limitless energy source of thefuture. According to a team ofresearchers led by Todd Evans of GeneralAtomics, California, the problematicELMs can be controlled cleverly. Theyfound that a small resonant magneticfield, derived from special coils locatedinside a reactor vessel, creates “chaotic”magnetic interference on the plasma

edge, which stops the fluxes fromforming. The experiments wereconducted at the General Atomics’ DIII-D National Fusion Facility, a tokamak inSan Diego. Nuclear fusion is the processwhich enables the Sun to radiate energy.In the case of our star, hydrogen atomsare forced together to produce helium.On Earth, the fusion would take place ina reactor fuelled by two isotopes ofhydrogen — deuterium and tritium —with helium the waste product.Deuterium is present in seawater, whichmakes it a virtually limitless resource.Tritium would be derived from irradiatingthe plentiful element lithium in the fusionvessel. Initially very high temperature,of the order of 108 oC, is needed tokickstart the fusion process, which thencould be sustained by tiny amounts offuel pellets.

ITER is designed to be a test bed offusion technologies, with a constructionperiod of about 10 years and anoperational lifespan of 20 years. Thepartners of the project are the EuropeanUnion (EU), the United States, Japan,Russia, China, India and South Korea.If ITER works, a prototype commercialreactor will be built, and if that works,fusion technology will be rolled outacross the world. Other problems facingfusion technology include the challengeof creating self-sustaining plasma andefficiently containing the plasma so thatcharged particles do not leak out.

Cosmic telescopes!

Researchers have evolved yet anotherinnovative technique to peep deeper intothe mysteries of the universe. A research

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team led by a Johns Hopkins Universityastronomer have used massive clustersof galaxies as “cosmic telescopes”. Whatthey have found may be infant galaxiesborn in the first billion years after thebeginning of the universe. According toHolland Ford, a professor in the HenryA. Rowland Department of Physics andAstronomy at the university’s KriegerSchool of Arts and Sciences, if thesefindings are confirmed, the extramagnification provided by thesegargantuan natural telescopes wouldgive astronomers their best-ever view ofgalaxies as they formed in the earlyuniverse, more than 12 billion years ago.Holland Ford is the head of the HubbleSpace Telescope’s Advanced Camera forSurveys Science Team, which alsoincludes researchers from the SpaceTelescope Science Institute, PUC in Chile,and other universities around the world.

Announcing the team’s results Fordsaid that their team’s spectroscopicobservations were made possible bygravitational lenses, the bending of lightcaused by gravity’s warping of space inthe presence of such massive objects asclusters of galaxies. Explaining the basicidea of gravitational lenses Ford recalledthat one of Einstein’s most startlingpredictions was that a gravitation fieldcan be thought of as a distortion of spaceand time. Gavitational lensing bymassive clusters of galaxies that haveabout 1 million billion times more massthan the sun provide one of the moststriking confirmations of Einstein’sprediction.

Ford asserts that our view of distantgalaxies behind a cluster can bemagnified by amounts that could vary

from barely detectable to as many as 50or 100 times normal size, depending onthe location of the galaxy and thedistribution of mass within the cluster.The clusters are, in effect, giant cosmictelescopes that allow astronomers to findand study distant galaxies that otherwisewould be too faint to study.

Astronomers want to know when thefirst galaxies formed, how large and howbright galaxies are at birth, and howgalaxies grow into large mature galaxieslike our home Milky Way galaxy. Theresearch team is searching for infantgalaxies that are less than a billion yearsold by comparing images of stronglylensing clusters taken by the HubbleSpace Telescope with images of the sameclusters taken by the Magellan, the VeryLarge Telescopes (VLT) and Geminitelescopes. The infant galaxies are so faraway their light is almost or entirelyredshifted to wavelengths that cannot bedetected with Hubble’s Advanced Camerafor Surveys, but can be detected withinfrared detectors on the world’s largesttelescopes.

Using this technique, the researchteam has searched for infant galaxiesbehind 14 lensing clusters. If longerspectroscopic observations of the threebrightest candidate galaxies confirm thatthey are indeed in the early universe,these galaxies will provide astronomerstheir clearest view yet of the youngestgalaxies ever seen.

(Source: Science Daily online)

60-year-old Plutonium questionsresolved

Scientists have claimed to solve a

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question about the nature of plutoniumthat has remained a mystery ever sincethe first nuclear device was detonated.It is known that plutonium behaves likeno other element in nature. The bondingof its electrons causes its crystalstructure to be uneven, similar to amineral, and the nucleus is unstable,causing the metal to spontaneouslydecay over time and damage thesurrounding metal lattice. First batchesof the plutonium metal used in thatdevice were too brittle due to the mineral-like structure of its crystal. In order tomake the metal machinable, the high-temperature, high-symmetry cubicstructure of plutonium needed to beretained at room temperature. In the firstnuclear device scientists achieved thisby adding a small amount of gallium.

According to Kevin Moore, a staffscientist in the Materials Science andTechnology Division at LawrenceLivermore National Laboratory, U.S.A.there was never a clear explanation asto why gallium stabilised the ductilecubic structure over the low-symmetrymineral-like structure; they just did itand it worked. For the first time,researchers have determined whygallium works. In pure plutonium, thebonds between Pu atoms are veryuneven, causing the metals highpropensity to adopt a low-symmetrystructure. However, when a gallium atomis put in the plutonium lattice, it causesthe bonds to become more uniform andthus leads to the high-symmetry cubicstructure. Gallium evens out theplutonium bonds, asserts Moore. Thecalculations strongly illuminate why

gallium stabilises the machinable cubicstructure to room temperature. Througha series of calculations, Moore and hisLivermore colleagues, Per Söderlind andAdam Schwartz, and David Laughlin ofCarnegie Mellon University haveproduced these results. The team nextproposes to test their calculations in thelaboratory.

New heart tissue grown in rats

Australian doctors have successfullygrown new beating heart tissue in ratsin a process that they claim could beused for people someday. The researcherssay the heart tissue developed by thembeats spontaneously with its own rhythmand could be used to repair heart attackdamage and other life-threateningailments. They say it is the first step tocreating organs to replace diseased andinjured body parts.

According to Dr. Wayne Morrison,who led a team of scientists from theBernard O’Brien Institute ofMicrosurgery this is a majorbreakthrough for Australian medicalscience. Though it may still be too earlyto put it in practice, but nevertheless itopens up the possibilities of growingliving tissue: taking the patient’s cellsand growing inside their own body livingtissue that can be used to repair theirown organs. The ground-breaking tissue-engineering technique uses a subject’sown heart cells to grow new tissue in aspecial chamber implanted in thesubject’s own body, which eliminates therisk of tissue rejection.

(Source: Science Daily)

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Magnetic thrust: fields force matterinto black holes

New observations confirm that magneticfields provide a final galactic pushneeded to plunge cosmic matter into ablack hole. The observations come froma system in the Milky Way called GROJ1655-40, which consists of a black holeand a normal star. Gas from the star ispulled toward the black hole, where itforms what’s called an accretion disk.Angular momentum keeps the discrevolving around the black hole insteadof falling into it. Until now, scientistsweren’t sure whether magnetic fields,radiation pressure, or heat alter the orbitand trigger that fall.

Unless something knocked them offcourse, the gases in the disk wouldcontinue to circle the black hole forever.“To get matter in toward the black hole,we have to change the orbits in the disk,”says study leader Jon Miller

Using NASA’s Chandra satelliteobservatory, Miller of the University ofMichigan in Ann Arbor, U.S.A. and histeam collected data on X- rays emittedfrom the J1655 system. They found thatthe X- rays came from a wind blowingfrom the disk, so some force must propelthe wind past the black hole’sgravitational pull. After simulating thewind on a computer, the researchersconclude that only magnetic fields couldcreate such a force. The team had ruledout a wind fuelled by heat from the coreof the disc or by pressure from radiationblasting out of the disk. A heat-drivenwind would have been hotter than theone that the researchers observed, andradiation pressure is too weak to drive

that wind. Therefore, magnetic pressurereally was the only viable meansremaining, according to Miller.

Such pressure could upset the gasdisc’s orbit in two ways. The magneticfields could push the wind outward likea spring, or the force of the spinning diskcould fling the wind away from the disk’scentre. Either disruption of the disc’sorbit would cause some matter to spiraldownward. Though most astrophysicistsexpected magnetic fields to play a role inblack holes, the finding of theresearchers is an important evidence tosupport that view because it is for thefirst time there is a clear evidence forwind coming off an accretion disc.According to Miller their finding couldhelp astrophysicists understand the“complex give-and-take between galaxiesand black holes.

(Source: Science News Online)

New finding about E Coli could helpcontain infections

Researchers at UT SouthwesternMedical Center, USA have discovered anew receptor in a strain of Escherichiacoli (E coli) that can be blocked to avertinfection. The finding might help indeveloping better therapies to treatbacterial infections resulting from foodpoisoning, diarrhea or plague. Thereceptor, known as QseC, is used by adiarrhea-causing strain of E coli toreceive signals from human flora andhormones in the intestine and expressvirulence genes to initiate infection.

In a study researchers havedescribed how they used phentolamine,an alpha blocker drug used to treat

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hypertension, to successfully impedesignalling to the receptor. Without suchsignals, bacteria then pass blindlythrough the digestive tract withoutinfecting cells. According to Dr. VanessaSperandio, Assistant Professor ofMicrobiology at UT Southwestern, U.S.A.and a member of the research team thisreceptor is found in many pathogens, sothey could use this knowledge to designspecific antagonists to block bacterialinfections.

Prior research by Dr. Sperandiofound that when a person ingests themore virulent enterohemorrhagic E coli,or EHEC — which is usually transmittedthrough contaminated food such as rawmeat — it travels peacefully through thedigestive tract until reaching theintestine. There, however, chemicalsproduced by the friendly gastrointestinalmicrobial flora and the human hormonesepinephrine and nor-epinephrine alertthe bacteria to its location. This cellularcross talk triggers a cascade of geneticactivations prompting EHEC to colonizeand translocate toxins into cells, alteringthe makeup of the cells and robbing thebody of nutrients. An infected personmay develop bloody diarrhoea or evenhaemolytic uremic syndrome, which cancause death in immune-weakenedpeople, the elderly and young children.

The new study identifies QseC as thespecific receptor by which EHEC sensesthe signals. When the receptor binds tosignalling molecules, the bacterium caninfect cells. Researchers tested thecapacity of adrenergic antagonists, drugssuch as alpha and beta blockers, todisrupt the receptor’s sensing ability.They found that phentolamine binds to

the QseC receptor and occupies thepocket that the receptor would use torecognise the host epinephrine and nor-epinephrine signals — thus blocking theQseC receptor from sensing the signalsand preventing it from being able toexpress its virulence genes in cells. Dr.Sperandio opined that this knowledgecould lead to further understanding ofthe signalling processes betweenmicrobes and humans and to thedevelopment of novel treatments ofbacterial infections with antagonists tothese signals.

New therapies are importantbecause treating some bacterialinfections with conventional antibioticscan cause the release of more toxins andmay worsen disease outcome. Theimportance of the research findings canbe magnified manifold because of theQseC receptor’s existence in other typesof bacteria. These include Shigella,which causes dysentery; Salmonella,which causes food poisoning andgastroenteritis; and Yersinia, whichcauses bubonic plague. All of them areinfectious diseases that afflict thousandsof people each year worldwide.Researchers are of the opinion thatoveruse of antibiotics has led bacteria todevelop resistance to antibiotics, so anovel type of therapy is needed.

(Source: Sciencedaily)

NASA Satellite positioning softwaremay aid in Tsunami warnings

University scientists using GlobalPositioning System (GPS) softwaredeveloped by NASA’s Jet PropulsionLaboratory, Pasadena, Calif., have

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shown that GPS can determine, withinminutes, whether an earthquake is bigenough to generate an ocean-widetsunami. This NASA-funded technologycan be used to provide faster tsunamiwarnings.

A team led by Dr. Geoffrey Blewitt ofthe Nevada Bureau of Mines and Geologyand Seismological Laboratory, Universityof Nevada, Reno, demonstrated that alarge quake’s true size can be determinedwithin 15 minutes using GPS data. Thisis much faster than is possible withmethods employed at present. Tsunamiwarning is a race against time assertsDr. Seth Stein, Department of GeologicalSciences, Northwestern University, anda member of the researcher team.Tsunamis travel at jet speed, so warningcentres must accurately decide, withinminutes, whether to issue alerts. Thishas to be done fast enough for thewarning to be distributed to authoritiesin impacted areas so they can implementresponse plans. Together withseismometer and ocean buoy data, GPSadds another tool that can improvefuture tsunami danger assessments.However, the first level of alert for largeearthquakes would always needseismology and ocean buoys to actuallysense the tsunami waves. The advantageof including GPS in warning systems isthat it would facilitate to quickly assesshow much the ocean floor has moved, sothat this information can directly settsunami models into motion.

The new method, called GPSdisplacement, works by measuring thetime radio signals from GPS satellitesarrive at ground stations located within

a few thousand kilometres of a quake.From these data, scientists can calculatehow far the stations moved because ofthe quake. They can then derive anearthquake model and the quake’s truesize, called its ‘moment magnitude.’ Thismagnitude is directly related to a quake’spotential for generating tsunamis.

As illustrated by the magnitude 9.2-9.3 Sumatra quake of December 2004,current scientific methods have difficultyin quickly determining momentmagnitude for very large quakes. Thatquake was first estimated at 8.0 usingseismological techniques designed forrapid analysis. Because thesetechniques derive estimates from thefirst seismic waves they record, they tendto underestimate quakes larger thanabout 8.5. That is the approximate sizeneeded to generate major ocean-widetsunamis. The initial estimate was theprimary reason warning centres in thePacific significantly underestimated theearthquake’s tsunami potential.

The potential of GPS to contribute totsunami warning became apparent afterthe Sumatra earthquake. GPSmeasurements showed that quakemoved the ground permanently morethan 1 centimetre as far away as India,about 2,000 kilometres away from theepicentre. The researchers hypothesisedthat if GPS data could be analysedrapidly and accurately, it could bepossible to quickly indicate theearthquake’s true size and tsunamipotential.

To test the feasibility of theirapproach, the scientists used NASA’ssatellite positioning data processing

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software to analyse data from 38 GPSstations located at varying distancesfrom the Sumatra quake’s epicentre. Thesoftware pinpoints a station’s preciselocation to within 7 millimetres. Only datathat were available within 15 minutes ofthe earthquake were used. Resultsindicated most of the permanent grounddisplacements occurred within a fewminutes of the arrival of the first seismicwaves. The analysis done by researchersinferred an earthquake model and amoment magnitude of 9.0, very near theearthquake’s final calculated size.

(Source: NASA News)

Good news and a puzzle

Ozone layer on the upper strata of theEarth’s atmosphere plays a vital role inprotecting life on the surface from theharmful glare of the sun’s strongestultraviolet rays, which can cause skincancer and other maladies. In the 1980s,when scientists noticed that manmadechemicals in the atmosphere weredestroying this layer, it is not surprisingthat people all over the world werealarmed. Governments quickly enactedan international treaty, called theMontreal Protocol, to ban ozone-destroying gases such as CFCs thenfound in aerosol cans and airconditioners.

Today, almost 20 years later, reportscontinue of large ozone holes openingover Antarctica, allowing dangerous UVrays through to Earth’s surface. Indeed,the 2005 ozone hole was one of the biggestever, spanning 24 million sq km in area,nearly the size of North America.Listening to this news, one might be

tempted to think that little progress hasbeen made. However, this assertion maynot be correct. While the ozone hole overAntarctica continues to open wide, theozone layer around the rest of the planetseems to be shrinking. For the last 9years, worldwide ozone has remainedroughly constant, halting the declinefirst noticed in the 1980s.

The question is why? Is the MontrealProtocol responsible? Or is some otherprocess at work? It’s a complicatedquestion. CFCs are not the only thingsthat can influence the ozone layer;sunspots, volcanoes and weather alsoplay a role. Ultraviolet rays fromsunspots boost the ozone layer, whilesulphurous gases emitted by somevolcanoes can weaken it. Cold air in thestratosphere can either weaken or boostthe ozone layer, depending on altitudeand latitude. These processes and othershave been presented in a review by agroup of researchers from NASA andsome universities in U.S.A. According toresearchers, they measured ozoneconcentrations at different altitudesusing satellites, balloons andinstruments on the ground. Then theycompared their measurements withcomputer predictions of ozone recovery.The calculations also took into accountthe known behaviour of the sunspotcycle, seasonal changes in the ozonelayer, and Quasi-Biennial Oscillations,a type of stratospheric wind patternknown to affect ozone.

What researchers have found is bothgood news and also a puzzle. The goodnews: In the upper stratosphere (aboveroughly 18 km), ozone recovery can beexplained almost entirely by CFC

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reductions. The Montreal Protocol seemsto be working at such heights, accordingto researchers. The puzzle: In the lowerstratosphere (between 10 and 18 km)ozone has recovered even better thanchanges in CFCs alone would predict.Something else must be affecting thetrend at these lower altitudes. The“something else” could be atmosphericwind patterns. This is because the windsare known to carry ozone from theequator to higher latitudes where it isdestroyed. Changing wind patterns affectthe balance of ozone and could beboosting the recovery below 18 km. Thisexplanation seems to offer the best fit tothe computer model of the researchers.However, other sources of natural ormanmade variability may yet prove to bethe cause of the lower-stratosphere’sbonus ozone. Whatever be the real cause,if the trend continues, the global ozonelayer should be restored to 1980 levelssometimes between 2030 and 2070. Bythen even the Antarctic ozone hole mightclose — for good.

(Source: NASA News)

Corkscrew Asteroid

Believe it or not the Earth has a “secondmoon” for early seven years. It is actuallyan Asteroid, only 20 metre in size, whichhas been going around our planet oncea year. The asteroid is too small to seewith the unaided eye — but it is there.

According to Paul Chodas of NASA’sNear Earth Object Program at JPL, theAsteroid arrived in 1999 and it’s beencorkscrewing around Earth ever since.Because the asteroid is so small andposes no threat, it has attracted little

public attention. But Chodas and otherexperts have been monitoring it, whichaccording to him is a very curious object.

Most near-Earth asteroids, whenthey approach Earth, simply fly by. Theycome and they go, occasionally makingnews around the date of closestapproach. This Asteroid since named2003 YN107 is different: It came and itstayed. Astronomers believe that 2003YN107 is one of a whole population ofnear-Earth asteroids that don’t just flyby Earth. They pause and corkscrew inour vicinity for years before moving along.These asteroids are called Earth Co-orbital Asteroids or “co-orbitals” for short.Essentially, they share Earth’s orbit,going around the Sun in almost exactlyone year. Occasionally a co-orbitalcatches up to Earth from behind, or viceversa, and the dance begins: Theasteroid, while still orbiting the sun,slowly corkscrews around our planet,which in other words means that theirorbit as seen from the earth appears likea corkscrew.

These asteroids, however, are nottruly captured by Earth’s gravity, notesChodas. But from our point of view, itlooks like we have a new moon.Astronomers know of at least four smallasteroids that can do this trick: 2003YN107, 2002 AA29, 2004 GU9 and 2001GO2. There may be more as Chodasbelieves the list will grow as asteroidsurveys improve in sky coverage andsensitivity. At the moment, only two co-orbitals are actually nearby: 2003 YN107and 2004 GU9. The others are scatteredaround Earth’s orbit.

2004 GU9 is perhaps the mostinteresting. It is about 200 metre in size,

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which is relatively large compared toother such asteroids. And according tolatest calculations it has been loopingaround Earth for 500 years—and maycontinue looping for another 500. It’s ina remarkably stable “orbit.”

Right now, however, researchers arepaying more attention to 2003 YN107 forone simple reason: it’s about to leave theearth’s orbit. The asteroid’s corkscrewpath is likely to come within 3.4 millionkm of Earth sometime in June 2006,when it will be slightly closer than usual.Earth’s gravity will then give the asteroidthe push it needs to leave. This wouldgive astronomers a rare chance toobserve the asteroids moving out of theearth’s orbit. However, it won’t be gone

forever. In about 60 years 2003 YN107will lap Earth again, resuming its roleas a temporary, corkscrewing moonlet.In due course, other coorbitals will do thesame.

Each encounter is an opportunity forstudy—and possibly profit. Even the mostpowerful telescopes cannot see much ofthese tiny asteroids; they’re just specksin the eyepiece. However, Chodas isoptimistic that one day, when the spaceprogram is more advanced it might bepossible to visit, explore the moonlets andtap their resources and then they wouldnot be just an object of curiosity as theyare today.

(Source: NASA NEWS on line)(Compiled and edited by: R. Joshi)

77B O O KR E V I E W

Book Review

Wings of Fire

A.P.J. ABDUL KALAM with ARUN TIWARI

Publisher: Universities Press (India) Ltd3-5-819, Hyderguda,Hyderabad - 500 029, pp. 179, Rs. 200.

India has made great strides in space,nuclear power and, above all, missiletechnology. Indeed Agni, Prithvi, Akash,Trishul and Nag have become householdnames in India and at the same time havecontributed to raising the nation to thelevel of a missile power of internationalreckoning. The man behind missiletechnology, aptly called the ‘missile man’,is none other than our honourablePresident, Dr. A.P.J. Abdul Kalam. Bornin 1931, the son of a little educated boat-owner in Rameswaram, Tamil Nadu, Dr.Kalam had an unparalleled career as adefence scientist, culminating in thehighest civilian award of India – theBharat Ratna. However, Dr. Kalam roseto the position he is enjoying today bydint of his personal and professionalstruggles. An account of Dr. Kalam’s lifecan, therefore, be inspiring andmotivating to youth, particularly thosebelonging to the unprivileged section ofthe society.

The book under review is anautobiography of Dr. Kalam written byArun Tiwari through a long seriesof sittings with the former. It is dividedinto four major chapters titledOrientation, Creation, Propitiation andContemplation.

The first Chapter ‘Orientation’described the struggles of Dr. Kalam’sboyhood and youth, bringing aliveeveryday life in a small town in SouthIndia named Rameswaram, and theinspirational roles of educators. Dr.Kalam’s dream to become an Air Forcepilot, got frustrated and he had tocontend with the job of Senior ScientificAssistant at the Directorate of TechnicalDevelopment & Production [DTD&P (Air)]of the Ministry of Defence. Later, he wasselected as a rocket engineer by theIndian Committee of Space Research(INCOSPAR). This chapter also narratesDr. Kalam’s efforts to design and developa hovercraft christened Nandi which,however, did not finally materialise.

The Chapter ‘Creation’ is mainlyabout the contribution of Dr. Kalam atIndian Space Research Organisation(ISRO). He was made the Project Managerof the Satellite Launch Vehicle (SLV)Programme. However, the firstexperimental flight trial of SLV-3 on 10August 1979 met with failure. Thisgreatly disappointed Dr. Kalam. But,he was not to be cowed down and, on 18July 1980, SLV-3 was successfullylaunched.

The third Chapter ‘Propitiation’highlights Dr. Kalam’s role at DefenceResearch and Development Laboratory(DRDL) in the development of missilesunder India’s prestigious IntegratedGuided Missile DevelopmentProgramme (IGMDP). The last Chapter‘Contemplation’ summarises some ideasof Dr. Kalam concerning technology, itsmanagement and the philosophy behindTechnology Management.

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The book under review is in essencea story of a scientist who, time andagain, was tested by failures andsetbacks but was finally crowned withsuccess and fame. As has been rightlyremarked in the book, one ‘need not bedisheartened about life. Problems are apart of life. Suffering is the essence ofsuccess.’ In this context it is worthquoting the following lines appearing inthe book:

God has not promisedSkies always blue,Flower-strewn pathwaysAll our life through;God has not promisedSun without rain,Joy without sorrowPeace without pain.

However, solace is also assured in termsof the following lines:

But God has promisedStrength for the day,Rest for the labourLight for the day.

There are words of wisdom scattered hereand there in the book. It will beworthwhile quoting the following lines:

Happiness, satisfaction, and success inlife depend on making the right choices,the winning choices. There are forces inlife working for you and against you. Onemust distinguish the beneficial forcesfrom the malevolent ones and choosecorrectly between them.

The following lines may also prove to berewarding reading indeed:

Total commitment is the commondenominator among all successful men

and women. Are you able to manage thestresses you encounter in your life? Thedifference between an energetic and aconfused person is the difference in theway their minds handle theirexperiences. Man needs his difficultiesbecause thay are necessary to enjoysuccess.

Then, how are the following words froma struggling Dr. Kalam of yesteryears:

So far, I had believed that the sky wasthe limit, but now it appeared that thelimits were much closer. There areboundaries that dictate life: you can onlylift so much weight; you can only learnso fast; you can only work so hard; youcan only go so far.!Also, reflecting on the title are thefollowing lines in the book:

Let the latent fire in the heart of everyIndian acquire Wings, and the glory ofthis great country light up the sky.

The book ends with the following hopeand prayer:

I earnestly hope and pray that thedevelopment ... will eventually make ourcountry strong and prosperous, a“developed” nation.

There are many inspiring anecdotesin the book, too. Certainly, a must-readnot only for youth but for readers of allage and also those belonging to variouscross-sections of the society.

P.K. MUKHERJEE

43, Deshbandhu Society15, PatparganjDelhi 110 092.