12 - · pdf fileelectrolytic cells and galvanic cells; lead accumulator, emf of a cell,...

Class - XII 3 Eduheal Foundation

CLASS ‐ XII S. No. Category Topic Page No.

1. Syllabus Guide Line 03

2. Explore Glass Stopping Bullet 08

3. Explore Do you Know? 10

4. Explore Squeeze me, Stretch me 11

5. Explore Bioluminescence - Fireflies and the future 14

6. Explore Microscopic Robots 17

7. Explore Why do clothes wrinkle? 19

8. Explore The shape of the Internet 20

9. Discover The Blue Bottle Reaction 22

10. Explore Bioplastics 24

11. Experiment Hydrogen production in your lab 28

12. Discover Eddy Currents 33

13. Invent Magnetic Pendulums 35

14. Interactive Activity International Space Station Alert 38

15. Explore What is the biological basis of consciouness 46

4 Class - XII Eduheal Foundation

CLASS VIII PHYSICS Electrostatics Electric Charges; Conservation of charge, Coulomb’s lawforce between two point charges, forces between multiple charges; superposition principle and continuous charge distribution. Electric field, electric field due to a point charge, electric field lines; electric dipole, electric field due to a dipole; torque on a dipole in uniform electric field. Electric flux, statement of Gauss’s theorem and its applications to find field due to infinitely long straight wire, uniformly charged infinite plane sheet and uniformly charged thin spherical shell (field inside and outside). Electric potential, potential difference, electric potential due to a point charge, a dipole and system of charges; equipotential surfaces, electrical potential energy of a system of two point charges and of electric dipole in an electrostatic field. Conductors and insulators, free charges and bound charges inside a conductor. Dielectrics and electric polarisation, capacitors and capacitance, combination of capacitors in series and in parallel, capacitance of a parallel plate capacitor with and without dielectric medium between the plates, energy stored in a capacitor. Van de Graaff generator. Current Electricity Electric current, flow of electric charges in a metallic conductor, drift velocity, mobility and their relation with electric current; Ohm’s law, electrical resistance, VI characteristics (linear and nonlinear), electrical energy and power, electrical resistivity and conductivity. Carbon resistors, colour code for carbon resistors; series and parallel combinations of resistors; temperature dependence of resistance. Internal resistance of a cell, potential difference and emf of a cell, combination of cells in series and in parallel. Kirchhoff’s laws and simple applica tions. Wheatstone bridge, metre bridge. Potentiometer principle and its applications to measure potential difference and for comparing emf of two cells; measurement of internal resistance of a cell. Magnetic Effects of Current and Magnetism Concept of magnetic field, Oersted’s experiment. Biot Savart law and its application to current carrying circular loop. Ampere’s law and its applications to infinitely long straight wire, straight and toroidal solenoids. Force on a moving charge in uniform magnetic and electric fields. Cyclotron. Force on a currentcarrying conductor in a uniform magnetic field. Force between two parallel currentcarrying conductorsdefinition of ampere. Torque experienced by a current loop in uniform magnetic field; moving coil galvanometerits current sensitivity and conversion to ammeter and voltmeter. Current loop as a magnetic dipole and its magnetic dipole moment. Magnetic dipole moment of a revolving electron. Magnetic field intensity due to a magnetic dipole (bar magnet) along its axis and perpendicular to its axis. Torque on a magnetic dipole (bar magnet) in a uniform magnetic field; bar magnet as an equivalent solenoid, magnetic field lines; Earth’s magnetic field and magnetic elements. Para, dia and ferro magnetic substances, with examples. Electromagnets and factors affecting their strengths. Permanent magnets. Electromagnetic Induction and Alternating Currents Electromagnetic induction; Faraday’s law, induced emf and current; Lenz’s Law, Eddy currents. Self and mutual inductance. Need for displacement current. Alternating currents, peak and rms value of alternating current/ voltage; reactance and impedance; LC oscillations (qualitative treatment only), LCR series circuit, resonance; power in AC circuits, wattless current. AC generator and transformer. Electromagnetic waves Electromagnetic waves and their characteristics (qualitative ideas only). Transverse nature of electromagnetic waves. Electromagnetic spectrum (radio waves, microwaves, infrared, visible, ultraviolet, Xrays, gamma rays) including elementary facts about their uses. Optics Reflection of light, spherical mirrors, mirror formula. Refraction of light, total internal reflection and its applica tions, optical fibres, refraction at spherical surfaces, lenses, thin lens formula, lensmaker’s formula. Magnifica


tion, power of a lens, combination of thin lenses in contact. Refraction and dispersion of light through a prism. Scattering of light blue colour of the sky and reddish appearance of the sun at sunrise and sunset. Optical instruments: Human eye, image formation and accommodation, correction of eye defects (myopia, hypermetro pia, presbyopia and astigmatism) using lenses. Microscopes and astronomical telescopes (reflecting and refracting) and their magnifying powers. Wave optics: wave front and Huygens’ principle, reflection and refraction of plane wave at a plane surface using wave fronts. Proof of laws of reflection and refraction using Huygens’ principle. Interference, Young’s double slit experiment and expression for fringe width, coherent sources and sustained interference of light. Diffraction due to a single slit, width of central maximum. Resolving power of microscopes and astronomical telescopes. Polarisation, plane polarised light; Brewster’s law, uses of plane polarised light and Polaroids. Dual Nature of Matter and Radiation Dual nature of radiation. Photoelectric effect, Hertz and Lenard’s observations; Einstein’s photoelectric equa tionparticle nature of light. Matter waveswave nature of particles, de Broglie relation. DavissonGermer experiment. Atoms & Nuclei Alphaparticle scattering experiment; Rutherford’s model of atom; Bohr model, energy levels, hydrogen spec trum. Composition and size of nucleus, atomic masses, isotopes, isobars; isotones. Radioactivityalpha, beta and gamma particles/rays and their properties; radioactive decay law. Massenergy relation, mass defect; binding energy per nucleon and its variation with mass number; nuclear fission and fusion. Electronic Devices Semiconductors; semiconductor diode – IV characteristics in forward and reverse bias, diode as a rectifier; I V characteristics of LED, photodiode, solar cell, and Zener diode; Zener diode as a voltage regulator. Junction transistor, transistor action, characteristics of a transistor; transistor as an amplifier (common emitter configu ration) and oscillator. Logic gates (OR, AND, NOT, NAND and NOR). Transistor as a switch. Communication Systems Elements of a communication system (block diagram only); bandwidth of signals speech, TV and digital data); bandwidth of transmission medium. Propagation of electromagnetic waves in the atmosphere, sky and space wave propagation. Need for modulation. Production and detection of an amplitudemodulated wave.

CHEMISTRY Solid State Classification of solids based on different binding forces: molecular, ionic, covalent and metallic solids, amor phous and crystalline solids (elementary idea), unit cell in two dimensional and three dimensional lattices, calculation of density of unit cell, packing in solids, voids, number of atoms per unit cell in a cubic unit cell, point defects, electrical and magnetic properties. Solutions Types of solutions, expression of concentration of solutions of solids in liquids, solubility of gases in liquids, solid solutions, colligative properties – relative lowering of vapour pressure, elevation of B.P., depression of freezing point, osmotic pressure, determination of molecular masses using colligative properties, abnormal molecular mass. Electrochemistry Redox reactions, conductance in electrolytic solutions, specific and molar conductivity variations of conduc tivity with concentration, Kohlrausch’s Law, electrolysis and laws of electrolysis (elementary idea), dry cell – electrolytic cells and Galvanic cells; lead accumulator, EMF of a cell, standard electrode potential, Nernst equation and its application to chemical cells, fuel cells; corrosion. Chemical Kinetics Rate of a reaction (average and instantaneous), factors affecting rates of reaction; concentration, temperature, catalyst; order and molecularity of a reaction; rate law and specific rate constant, integrated rate equations and half life (only for zero and first order reactions); concept of collision theory (elementary idea, no mathematical treatment)


Surface Chemistry Adsorption – physisorption and chemisorption; factors affecting adsorption of gases on solids; catalysis : homogenous and heterogeneous, activity and selectivity: enzyme catalysis; colloidal state: distinction be tween true solutions, colloids and suspensions; lyophilic, lyophobic, multimolecular and macromolecular colloids; properties of colloids; Tyndall effect, Brownian movement, electrophoresis, coagulation; emulsion – types of emulsions. General Principles and Processes of Isolation of Elements Principles and methods of extraction concentration, oxidation, reduction electrolytic method and refining; occurrence and principles of extraction of aluminium, copper, zinc and Iron. pBlock Elements Group 15 elements: General introduction, electronic configuration, occurrence, oxidation states, trends in physical and chemical properties; nitrogen preparation, properties and uses; compounds of nitrogen: prepa ration and properties of ammonia and nitric acid, oxides of nitrogen (structure only); Phosphorousallotropic forms; compounds .of phosphorous: preparation and properties of phosphine, halides (PCl3, PCl5) and oxoacids (elementary idea only) Group 16 elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties; dioxygen: preparation, properties and uses; simple oxides; Ozone. Sulphur allotropic forms; compounds of sulphur: preparation, properties and uses of sulphur dioxide; sulphuric acid: industrial process of manufacture, properties and uses, oxoacids of sulphur (structures only). Group 17 elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties; compounds of halogens: preparation, properties and uses of chlorine and hydrochloric acid, interhalogen compounds, oxoacids of halogens (structures only). Group 18 elements:General introduction, electronic configuration. Occurrence, trends in physical and chemi cal properties, uses. d and f Block Elements General introduction ,electronic configuration, occurrence and characteristics of transition metals, general trends in properties of the first row transition metals – metallic character, ionization enthalpy, oxidation states, ionic radii, colour catalytic property, magnetic properties, interstitial compounds, alloy formation. Preparation and properties of K2Cr2O7 and KMnO4. Lanthanoids electronic configuration, oxidation states, chemical reactivity and lanthanoid contraction. Actinoids Electronic configuration, oxidation states. Coordination Compounds Coordination compounds Introduction, ligands, coordination number, colour, magnetic properties and shapes, IUPAC nomenclature of mononuclear coordination compounds. bonding; isomerism, importance of coordina tion compounds (in qualitative analysis, extraction of metals and biological systems). Haloalkanes and Haloarenes Haloalkanes:Nomenclature, nature of CX bond, physical and chemical properties, mechanism of substitution reactions. Haloarenes: Nature of CX bond, substitution reactions (directive influence of halogen for monosubstituted compounds only) Uses and environmental effects of dichloromethane, trichloromethane, tetrachloromethane, iodoform, freons, DDT. Alcohols, Phenols and Ethers Alcohols:Nomenclature, methods of preparation, physical and chemical properties (of primary alcohols only); identification of primary, secondary and tertiary alcohols; mechanism of dehydration, uses, some important compounds methanol and ethanol. Phenols :Nomenclature, methods of preparation, physical and chemical properties, acidic nature of phenol, electrophillic substitution reactions, uses of phenols. Ethers:Nomenclature, methods of preparation, physical and chemical properties, uses. Aldehydes, Ketones and Carboxylic Acids


Aldehydes and Ketones:Nomenclature, nature of carbonyl group, methods of preparation, physical and chemi cal properties, and mechanism of nucleophilic addition, reactivity of alpha hydrogen in aldehydes; uses. Carboxylic Acids: Nomenclature, acidic nature, methods of preparation, physical and chemical properties; uses. Organic compounds containing Nitrogen Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical properties, uses, identification of primary, secondary and tertiary amines. Cyanides and Isocyanides will be mentioned at relevant places in context. Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry. Biomolecules Carbohydrates Classification (aldoses and ketoses), monosaccahrides (glucose and fructose), oligosaccha rides (sucrose, lactose, maltose), polysaccharides (starch, cellulose, glycogen); importance. Proteins Elementary idea of a amino acids, peptide bond, polypeptides proteins, primary structure, econdary structure, tertiary structure and quaternary structure (qualitative idea only), denaturation of proteins; enzymes. Vitamins Classification and functions.Nucleic Acids:DNA & RNA . Polymers Classification natural and synthetic, methods of polymerization (addition and condensation), copolymeriza tion. Some important polymers: natural and synthetic like polythene, nylon, polyesters

BIOLOGY SEXUAL REPRODUCTION Pollination and fertilization in flowering plants. Development of seeds and fruits. Human reproduction: repro ductive system in male and female, menstrual cycle. Production of gametes, fertilization, implantation, ,embryo development, pregnancy and parturation. Reproductive health birth control, contraception and sexually transmitted diseases. Genetics and evolution Mendelian inheritance. Chromosome theory of inheritance, deviations from Mendelian ratio (gene interaction Incomplete dominance, codominance, complementary genes, multiple alleles). Sex determination in human beings: XX, XY. Linkage and crossing over. Inheritance pattern of haemophilia and blood groups in human beings. DNA: replication, transcription, translation. Gene expression and regulation. Genome and Human Genome Project. DNA fingerprinting. Evolution: Theories and evidences. BIOLOGY AND HUMAN WELFARE Animal husbandry. Basic concepts of immunology, vaccines. Pathogens, Parasites. Plant breeding, tissue culture, food production. Microbes in household food processing, industrial production, sewage treatment and energy generation. Cancer and AIDS. Adolescence and drug/alcohol abuse. BIOTECHNOLOGY AND ITS APPLICATIONS Recombinant DNA technology. Applications in Health, Agriculture and Industry Genetically modified (GM) organisms; biosafety issues. Insulin and Bt cotton ECOLOGY & ENVIRONMENT Ecosystems: components, types and energy flow. Species, population and community. Ecological adaptations. Centres of diversity and conservation of biodiversity, National parks and sanctuaries. Environmental issues.


At first glance, bullet-resistant glass looks identical to an ordinary pane of glass, but that‛s where the similarities end. An ordinary piece of glass shatters when struck by a single bullet. Bullet resistant glass is designed to withstand one or several rounds of bullets depending on the thickness of the glass and the weapon being fired at it. So, what gives bullet-resistant glass the ability to stop bullets?

Different manufacturers make different variations of bullet-resistant glass, but it is basically made by layering a polycarbonate material between pieces of ordinary glass in a process called lamination. This process creates a glass-like material that is thicker than normal glass. Polycarbonate is a tough transparent plastic — Bullet-resistant glass is between 7 millimeters and 75 millimeters in thickness. A bullet fired at a sheet of bullet-resistant glass will pierce the outside layer of the glass, but the layered polycarbonate-glass material is able to absorb the bullet‛s energy and stop it before it exits the final layer.

The ability of bullet-resistant glass to stop a bullet is determined by the thickness of the glass. A rifle bullet will collide with the glass with a lot more force than a bullet from a handgun, so a thicker piece of bullet-resistant glass would be needed to stop a rifle bullet as opposed to a handgun bullet.

There is also one-way bullet-resistant glass available, which has one side able to stop bullets, while the other side allows bullets to pass through it unaffected. This gives a person being shot at the ability to shoot back. This type of bullet-

Glass Stopping Bullet


resistant glass is made by laminating a brittle sheet of material with a flexible material.

Imagine a car equipped with this one-way bullet-resistant glass. If a person outside the car shoots a bullet into the window, the bullet would strike the brittle side first. This brittle material would shatter around the point of impact and absorb some of the energy over a large area. The flexible material then absorbs the remaining energy of the bullet, stopping the bullet. A bullet fired from inside the same car would easily pass through the glass because the bullet‛s force is concentrated on a small area, which causes the material to flex. This causes the brittle material to break outwards, allowing the bullet to pierce the flexible material and strike its target.

Q. Why does fog appear only at dawn and not at dusk?

Ans.: Fog is nothing but a cloud on earth. During the day time, due to the heat of the sun, the water on the surface of the earth evaporates and is carried up with the hot air which is lighter than the cold air. Therefore there is no fog at dusk. But during cold nights, the vapour does not rise and remains suspended over the surface on the earth, which is seen as fog at dawn.

Q. Why are medicines administered in doses and not all at one shot?

Ans.: Drugs that we consume contain some toxic material. When it is consumed in small quantities it does not affect the body as the body has something called maximum toxic level (MTL). When the quantity of the drug is small the toxic level in the body is less and it starts acting against the disease.

With time, the toxic level starts falling and at one stage the toxic level lowers to zero. It is at this stage that we are supposed to take the next dose. But on consuming a high dosage of the drug, the toxic level of the body crosses the MTL and the drug consumed can no longer act against the disease in the body. Hence, doctors prescribes drugs in regulated doses.


Q. Why does water, which is colourless, become white when it freezes? Ans.: In liquid state the arrangement of molecules in water is such that light can pass through them and it looks colourless. When water freezes and become ice, the molecular arrangement is rigid and there is no room for light to pass through, making it white. Q. When both iron and steel are made of raw iron, why does iron get attracted to magnets and not steel? Ans.: Alloy steel or special steel, popularly called stainless steel, is non-magnetic because it contains 18 percent chromium, 8 percent nickel and 74 percent steel. There are several types of stainless steel, which contain chromium ranging from 4 to 22 per cent and nickel from 0 to 26 per cent. Since the alloy contains non- ferrous compounds upto 26 per cent, stainless steel does not get attracted to magnet. Q. What is fibre glass? How does it differ from ordinary glass? Ans.: Glass is a supercooled liquid which forms a non-crystalline solid. It is a hard, brittle amorphous material which is usually transparent or translucent and resistant to chemical attack. On the other hand, glass fibre is glass melted and drawn into fibres. The fibres are then impregnated with resin to produce a material that is both strong and corrosion resistant. Q. What is the difference between drug and medicine? Ans.: Medicine is used to treat a disease or illness, while drugs are used in dying or chemical operations and is a term used for narcotics like heroin, morphine and cocaine. Drugs are also used for manufacturing medicines. Q. Why does the temperature of boiling liquid remain constant even when heating continues? Ans.: As a liquid reaches its boiling point, the liquid starts converting into vapours. The conversion requires some work done, which in turn requires some energy. Thus, the energy required to do the work is supplied by the source of heat of vaporisation of the liquid. Thus, even when the liquid is receiving heat energy constantly from the source, the temperature of the liquid does not rise.

n

Do You Know ?


At this very moment, disturbances from outer space are stretching and squeezing you. Knowing exactly when and by how much you are squashed or stretched will enable humans to learn much more about our universe, perhaps even telling us more about the Big Bang, or shedding light on the mystical “dark matter” that is postulated to exist in huge quantities throughout the universe.

Making waves

This stretching and squeezing is due to gravity waves, also known as gravitational radiation. Every heavy object that is changing speed or direction makes gravity waves. These waves move through space in the same way that light does - even at the same speed. But, unlike light waves, if a gravity wave passes through your neighbourhood, it will (temporarily!) change the distances between everything - even the distance between your navel and your spine. But this isn‛t a miracle slimming event, nor will anyone notice you looking plumper than usual. These waves, and the amount they change the distances between objects, are very tiny. A big wave will change the distance between two objects by one- billionth the distance from one side of an atom to the other. This change is

Squeeze me, Stretch me


equivalent to a change in the distance between the Earth and its nearest star (four light-years away) by a tenth of a millimetre.

Gravity waves are among the consequences of Einstein‛s General Theory of Relativity. It basically says that the curvature of spacetime is equal to the matter in it. If you take a large flat rubber sheet (and call it spacetime), and put a bowling ball (matter) in the middle of it, the rubber sheet becomes curved. If you put different matter on the sheet, it curves differently. On the rubber sheet, before you put the ball on it, the shortest distance between two points is a straight line. When you put something heavy in the middle, you can no longer go in a straight line staying on the sheet, and the shortest distance is called a geodesic.

Light always takes the shortest path, so it always travels along geodesics. Since geodesics aren‛t always straight, light doesn‛t always travel in straight lines. If a star is hiding behind our sun, it is possible that we could still see it, because light travelling from it to us can be bent around the sun. Durring a total solar eclipse, the sun vanished behind the moon, and the physicists could see the stars that were normally hidden by the sun‛s glow. Their measurements showed that at least two of the stars they could see were in fact the same star, with light taking different paths, bending around our sun, to get here. Einstein and his theory became instantly famous.

If you are finding it hard to imagine how there can be more than one “shortest way” between two points, here is an analogy. If you want to get to New Zealand from England by the quickest way, you can actually leave England pointing any direction you want. This is because the Earth is curved, and because New Zealand is on the opposite side of it.


Playing gravity detective

The tiny size of gravity waves has made them very difficult to find. Einstein first predicted in 1918 that heavy objects, such as two stars moving around each other, would give off gravity waves. Since then, many people have tried to find them - to do so would be more evidence for the theory of relativity, and would give us a new, powerful way of looking at the universe.

The best way to detect gravity waves would be to measure one of those tiny changes in distance they cause. This could be done by getting something large, with ends exactly parallel, and then constantly measure the distance between the ends. If the distance changes, you‛ve detected a gravity wave.

But it‛s not that simple. If a car goes past on the road beside your laboratory, it will shake the ground and your detector, causing a change in distance far greater than anything caused by the wave you are trying to find. Then there‛s also the problem of the atoms in your detector. They jiggle around, as all atoms do, all the time. Again, this jiggling has a much greater effect than a gravity wave.

There is hope, however. There are currently several projects around the world that will start working within a few years. For example, there is LISA (Laser Interferometer Space Antenna), a space-based system that uses lasers and mirrors. Another is LIGO (Laser Interferometer Gravitational wave Observatory), which uses the same type of system. Both these systems split a laser beam into two parts, send them a long distance at right angles to each other, and then reflect them back. When the beams are joined again, the resulting interference pattern will show whether there is any distance change. If these detectors overcome the difficulties faced during earlier experiments, we can expect to have a whole new way of looking at the stars.


Bioluminescence: Fireflies and the Future

As children we were always fascinated by the soft glow of the fireflies. We used to chase after their tiny flashing bodies just to see if we could get close enough to one to figure out how they work. What is so engaging about them? Light is such a powerful force in our universe and the idea of an organism being able to create its own light is an incredibly exciting concept. How are they able to create this “light”? And why is it useful for their survival? Fireflies must utilize this fairly unique ability for some important purpose. Could these light producing fireflies teach us anything about life?

Why Do Fireflies Glow? Organisms that produce light are referred to bioluminescent organisms. Bioluminescence is defined as “the process wherein light is produced by a chemical reaction which originates in the organism”. Bioluminescence is mostly a phenomenon found at the bottom of the ocean floor, but fireflies also possess this ability. They emit a soft light and are often called “lightning bugs” because of the way they flash their light on and off. Contrary to what one might think, the glow that the fireflies give off is not used to attract or deter their prey. On the other hand, fireflies use different intermittent signals in order to capture the attention of a possible future mate. Both sexes of fireflies use a specific flash pattern that can range anywhere from a short burst to a long continuous flashing sequence. Within any given population, there are many different species of fireflies and each species has a distinct signal. Males and females locate each other by recognizing their specific sequences. Since mating is essential to survival, attracting a mate can sometime become an aggressive game. It is not unusual in this game for a specific female species of firefly to fake their signals in order to confuse and lure a male from another species for the sole purpose of eliminating him. Overall, the firefly‛s lantern is essentially a courtship device; but how does the firefly actually make light?


How Does Bioluminescence Work?

The light that a firefly creates is the result of combination of four different ingredients. This light is produced through a chemical reaction involving Luciferin, which is a substrate, Luciferase, an enzyme, ATP, and oxygen. The light producing section of the body is located in the sixth or seventh abdominal section of the firefly. It is within this cavity that the two compounds Luciferin and Luciferase are stored. A firefly will draw oxygen in through its complex system of air tubes and expose the oxygen to the Luciferin and the Luciferin will then oxidize and activate the Luciferase. This will generate a light that will shine through the skeleton of the abdomen. It is important to note that scientists disagree about the method that the fireflies use to control the duration of their flashes. One theory, known as the “Oxygen Control Theory”, explains that fireflies can control the length and duration of their light by regulating the amount of oxygen that they intake. If little or no oxygen reaches the part of the firefly known as the phonic organ, the chemical reaction will not be extremely strong and the light of the firefly will not shine very brightly or for a lengthy duration. Another theory, known as the “Neural Activation Theory” states that fireflies have neural control over the activity of structures called “tracheal end cells”. These structures aid in the initiation of the chemical reaction. Whether or not the fireflies have physical or neural control over their ability to produce light, their method of creating the light that emanates from their bodies is extremely efficient. Very little heat is given off of this light which means that not very much energy is wasted at all. This “cold light” has a 96% efficiency rating; which, when compared to an incandescent light that has only 10% efficiency, is rather impressive.

How Useful is Bioluminescence? Bioluminescence is because fireflies create light due to a chemical reaction that depends on the presence of ATP. If ATP is present in a sample of something, that is a good indication that life is occurring within that specimen. NASA has considered using this method to test for life on other planets. If these firefly compounds were mixed with samples and they produced a glowing reaction, that would mean that the presence of ATP would be highly likely. Biologists are also


using this approach to fight Tuberculosis. If the enzyme Luciferase is added to a cultured sample of Tuberculosis and an antibiotic is also added, the strength of the antibiotic can be tested. If the drug fails, then the bacteria will continue to thrive and glow. This method enables researches and doctors to cut the time needed for drug treatments to just three days instead of three months. This research has also been employed in gene activation therapy cases, where ultraviolet cameras seek out genes treated with Luciferase. If light is visible, this means that the Luciferase gene is active.

Although we have to know a lot about bioluminescence and fireflies, but the findings of the experiments with Luciferin, Luciferase, and ATP can lead scientists to new and exciting discoveries.

So Much More to Know … From the nature of the cosmos to the nature of societies, the following top 25 questions span the sciences. These questions are either unanswered or partially answered. Some are pieces of questions others are big questions in their own right. Some will drive scientific inquiry for the next century; others may soon be answered. Many will undoubtedly spawn new questions. > What Is the Universe Made Of? > What is the Biological Basis of Consciousness? > Why Do Humans Have So Few Genes? > To What Extent Are Genetic Variation and Personal Health Linked?

> Can the Laws of Physics Be Unified? > How Much Can Human Life Span Be Extended?

> What Controls Organ Regeneration? > How Can a Skin Cell Become a Nerve Cell? > How Does a Single Somatic Cell Become a Whole Plant?

> How Does Earth’s Interior Work? > Are We Alone in the Universe? > How and Where Did Life on Earth Arise? > What Determines Species Diversity? > What Genetic Changes Made Us Uniquely Human?

> How Are Memories Stored and Retrieved? > How Did Cooperative Behavior Evolve? > How Will Big Pictures Emerge from a Sea of Biological Data?

> How Far Can We Push Chemical Self Assembly?

> What Are the Limits of Conventional Computing?

> Can We Selectively Shut Off Immune Responses?

> Do Deeper Principles Underlie Quantum Uncertainty and Nonlocality?

> Is an Effective HIV Vaccine Feasible? > How Hot Will the Greenhouse World Be? > What Can Replace Cheap Oil — and When?

> Will Malthus Continue to Be Wrong?


Microscopic Robots Tiny robots small enough to enter the human body are being developed by researchers for a variety of purposes including treating cancer, drug delivery, and even the growth of new cells and tissues.

Doctors are often faced with the challenge of performing microsurgery to repair blood vessels, transplant tissue or reattach a severed limb. These proce- dures are very intricate, and surgery is often not the most effective solution since it can be very invasive and difficult to conduct. Soon, many surgeons could be turning to nanotechnology and performing delicate tasks by remote controled tiny robots, similar in size to a grain of rice, that could travel through the body.

In Japan, a group of scientists have designed tiny spinning screws that can swim through veins in the body. They can potentially burrow into tumours to kill them or deliver drugs to a specific tissue or organ. Since they are so small, they could be injected into the body using a standard hypodermic needle and once inside, could be magnetically steered around the body using a 3D magnetic field supply and controller. These devices will be particularly useful for removing brain tumours since they are difficult to operate on.

Miniature motors Instead of relying on a magnetic field, other researchers are creating microrobots powered by tiny motors that could swim through the body and help with diagnosing and treating certain conditions. A team of scientist in Australia have already built a liner motor, the size of a salt crystal, but they are now working to create an even smaller one the width of two human hairs. Its propulsion mechanism is similar to the bacteria E. coli. A rotating motor whirls the flagella around its axis, much like a stockwhip, and if it is in a liquid, it screws its way through the fluid. It can spin 100,000 times a second.

Living Robots? Other Microrobots being created are not solely machines. Several institutes have been involved in incorporating organic living tissue with inorganic components to create hybrid devices that are part machine, part organism. The first such devices were self-assembling microbots powered by living heart muscle, created


by engineers at the University of California Los Angeles (UCLA). Each tiny robot is composed of an arch of gold connected to a sheath of cardiac muscle grown from rat cells, and if released in the body, it feeds off glucose in the blood to get energy to move. To test the microbots, the researchers immersed them in a protein and sugar solution that mimicked internal body conditions. As the heart muscle contracted and then relaxed, the microbot could be seen to ‘walk‛ forward. These microbots could potentially be used in microsurgery, for example to clear out the build up of plaques within arteries. The technology also has potential for creating new legs or fingers for amputees by allowing new muscle cells to grow over artificial bones.

But research into these various methods is still in its infancy and there are many problems to overcome. TThey are now looking to see if using skeletal muscle instead of heart muscle could help the robots move more freely: heart muscle tends to beat at its own rhythm and so is hard to control. Using electricity to stimulate skeletal muscle could allow researchers to turn the robots on and off, and extend their use to sources of power for tiny body implants or mini electrical generators that power computer chips.

Photo of E. coli bacterium taken under a Transmission Electron Microscope. Microbots being developed at Monash Univeristy mimic its movement.


Why Do Clothes Wrinkle? Heat and water cause wrinkles. Heat breaks the bonds holding polymers in place within the fibres of a fabric. When the bonds are broken, the fibres are less rigid with respect to each other, so they can shift into new positions. As the fabric cools, new bonds form, locking the fibres into a new shape. This is both how ironing gets wrinkles out of your clothes and why letting clothes cool in a heap fresh from the dryer will instill wrinkles. Not all fabrics are equally susceptible to this type of wrinkling. Nylon, wool, and polyester all have a glass transition temperature, or temperature below which the polymer molecules are almost crystalline in structure and above which the material is more fluid, or glassy.

Water is the key culprit behind wrinkling of cellulose-based fabrics, such as cotton, linen, and rayon.

The polymers in these fabrics are linked by hydrogen bonds, which are the same bonds that hold together molecules of water. Absorbent fabrics allow water molecules to penetrate the areas between the polymer chains, permitting the formation of new hydrogen bonds. The new shape becomes locked in as the water evaporates. Steam ironing works well on removing these wrinkles.

Permament Press Fabrics In the 1950s, scientists came up with a process for treating a fabric to render it wrinkle free, or permanent press. This worked by replacing the hydrogen bonds between polymer units with water-resistant cross-linked bonds. However, the crosslinking agent was formaldehyde, which was toxic, smelled bad, and made the fabric itchy, plus the treatment weakened some fabrics by making them more brittle. A new treatment was developed in 1992 that eliminated most of the formaldehyde from the fabric surface. This is the treatment used today for many wrinkle-free cotton garments.

Ironing uses heat and steam to remove wrinkles


The Shape of the Internet The Internet is the greatest gift of 20 th century. The Internet is really good at connecting people. It seems so simple, but the Internet is a complex web of connections. And that web looks a lot like a medusa jellyfish, according to new research by scientists in Israel. Within the Internet, there is a dense core of connections surrounded by lots of tentacle-like links. Until now, scientists have had a hard time mapping the structure of the Internet. That‛s because it formed almost by accident in the 1960s and 1970s, when universities, government agencies, and compa- nies first decided to link their computer networks so that they could share information. The Internet grew as new groups added their computer systems to the structure. Today, when you send an e-mail to a friend next door, it can pass through as many as 30 small networks—or subnetworks—before it arrives at its destination just a split second later. Researchers have tried to understand the shape of the Internet before. Their attempts have involved software that sends packets of information to specific destinations and tracks their routes. The packets work like probes, revealing details about which subnetworks they travel through on their way. But until recently, scientists were able to send probes from only a small number of sites. With such a limited number of starting points, the information stayed close to home. The probes missed more distant sites and links. This has been such a big problem that “there was a growing opinion before the new study that one really couldn‛t measure the Internet.” Some Scientist found a way. They enlisted volunteers to help them send probes from more than 12,000 computers around the world. Following these probes, the scientists counted how many routes connected each subnetwork to the others. This widespread method revealed three layers within the Internet. At the core

A new map of the Internet shows a core of tight connections and an outer ring of looser connections.


of the virtual jellyfish are about 100 of the most tightly connected subnetworks. These include some subnetworks such as Google. Surrounding this core is a much larger group of subnetworks that have lots of connections to each other and to the core. Finally, about one fifth of the Internet‛s subnetworks can communicate to the rest of the world only by sending information through the core. The scientists compare these fringe subnetworks to the tentacles of a jellyfish. Because 80 percent of subnetworks can reach each other without going through the core, the new map suggests that the Internet is less vulnerable than scientists previously thought. Attacks or outages to any one part of the Internet probably wouldn‛t take out the whole system.

(Continued from page 16) One of such question and its partial answer is illustrated below.

How Does a Single Somatic Cell Become a Whole Plant? It takes a certain amount of flexibility for a plant to survive and reproduce. It can stretch its roots toward water and its leaves toward sunlight, but it has few options for escaping predators or finding mates. To compensate, many plants have evolved repair mechanisms and reproductive strategies that allow them to produce offspring even without the meeting of sperm and egg. Some can reproduce from outgrowths of stems, roots, and bulbs, but others are even more radical, able to create new embryos from single somatic cells. Most citrus trees, for example, can form embryos from the tissues surrounding the unfertilized gametes—a feat no animal can manage. The houseplant Bryophyllum can sprout embryos from the edges of its leaves. Nearly 50 years ago, scientists learned that they could coax carrot cells to undergo such embryogenesis in the lab. Since then, people have used socalled somatic embryogenesis to propagate dozens of species, including coffee, magnolias, mangos, and roses. A Canadian company has planted entire forests of fir trees that started life in tissue culture. But like researchers who clone animals, plant scientists understand little about what actually controls the process. The search for answers might shed light on how cells’ fates become fixed during development, and how plants manage to retain such flexibility. Scientists aren’t even sure which cells are capable of embryogenesis. Although earlier work assumed that all plant cells were equally labile, recent evidence suggests that only a subset of cells can transform into embryos. But what those cells look like before their transformation is a mystery. Researchers have videotaped cultures in which embryos develop but found no visual pattern that hints at which cells are about to sprout, and staining for certain patterns of gene expression has been inconclusive. Researchers do have a few clues about the molecules that might be involved. In the lab, the herbicide 2,4dichlorophe noxyacetic acid (sold as weed killer and called 2,4D) can prompt cells in culture to elongate, build a new cell wall, and start dividing to form embryos. The herbicide is a synthetic analog of the plant hormones called auxins, which control everything from the plant’s response to light and gravity to the ripening of fruit. Auxins might also be important in natural somatic embryogenesis: Embryos that sprout on top of veins near the leaf edge are exposed to relatively high levels of auxins. Recent work has also shown that over or underexpression of certain genes in Arabidopsis plants can prompt embryogenesis in otherwise normallooking leaf cells. Sorting out sexfree embryogenesis might help scientists understand the cellular switches that plants use to stay flexible while still keeping growth under control. Developmental biologists are keen to learn how those mechanisms compare in plants and animals. Indeed, some of the processes that control somatic embryogenesis may be similar to those that occur during animal cloning or limb regeneration. On a practical level, scientists would like to be able to use labpropagation techniques on crop plants such as maize that still require normal pollination. That would speed up both breeding of new varieties and the production of hybrid seedlings—a flexibility that farmers and consumers could both appreciate.


The Blue Bottle Reaction In this chemistry demonstration, a blue solution gradually becomes clear. When the flask of liquid is swirled around, the solution becomes blue again. The blue bottle reaction is easy to perform and uses readily-available materials. Materials Required : tap water two 1-litre erlenmeyer flasks with stoppers 7.5 g glucose (2.5 g for one flask; 5 g for the other flask) 7.5 g sodium hydroxide NaOH (2.5 g for one flask; 5 g for the

other flask) 0.1% solution of methylene blue (1 ml for each flask) Procedure 1. Half-fill two one-litre Erlenmeyer flasks with tap water and mark them A & B respectively. 2. Dissolve 2.5 g of glucose in one of the flask (flask A) and 5 g of glucose in the other flask (flask B). 3. Dissolve 2.5 g of sodium hydroxide (NaOH) in flask A and 5 g of NaOH in flask B. 4. Add 1 ml of 0.1% methylene blue to each flask. 5. Stopper the flasks and shake them to dissolve the dye. The resulting solution will be blue. 6. Set the flasks aside . The liquid will gradually become colourless as glucose is oxidized by the dissolved dioxygen. The effect of concentration on reaction rate should be obvious. The flask with twice the concentration uses the dissolved oxygen in about half the time as the other solution. A thin blue boundary can be expected to remain at the solution-air interface, since oxygen remains available via diffusion. 7. The blue colour of the solutions can be restored by swirling or shaking the contents of the flask. 8. The reaction can be repeated several times.


How the Blue Bottle Reaction Works In this reaction, glucose (an aldehyde) in an alkaline solution is slowly oxidized by dioxygen to form gluconic acid: CH 2 OH–CHOH–CHOH–CHOH–CHOH–CHO + 1/2 O 2 —> CH 2 OH–CHOH–CHOH– CHOH–CHOH–COOH Gluconic acid is converted to sodium gluconate in the presence of sodium hydroxide. Methylene blue speeds up this reaction by acting as an oxygen transfer agent. By oxidizing glucose, methylene blue is itself reduced (forming leucomethylene blue), and becomes colourless. If there is a sufficient available oxygen (from air), leucomethylene blue is re- oxidized and the blue colour of solution can be restored. Upon standing, glucose reduces the methylene blue dye and the colour of the solution disappears. How to Do the Blue Bottle Chemistry Demonstration - Other Colours In addition to the blue -> clear -> blue of the methylene blue reaction, other indicators may be used for different colour-change reactions. For example, resazurin (7-hydroxy-3H-phenoxazin-3-one-10-oxide, sodium salt) produces a red -> clear -> red reaction when substituted for methylene blue in the demonstration. The indigo carmine reaction is even more eye-catching, with its green -> red/yellow -> green colour change. How to Perform the Indigo Carmine Colour Change Reaction 1. Prepare a 750 ml aqueous solution with 15 g glucose (solution A) and a 250 ml aqueous solution with 7.5 g sodium hydroxide (solution B). 2. Warm solution A to body temperature (~36-38°C). Warming the solution is important. 3. Add a ‘pinch‛ of indigo carmine You want a quantity sufficient to make solution A visibly blue. 4. Pour solution B into solution A. This will change the colour from blue -> green. Over time, this colour will change from green -> red/golden yellow. 5. Pour this solution into an empty beaker, from a height of ~60 cm. Vigorous pouring from a height is essential in order to dissolve dioxygen from the air into the solution. This should return the colour to green. 6. Once again, the colour will return to red/golden yellow.


Bioplastics Turning Wheat And Potatoes into Plastics

In the past, fields of wheat and rows of potatoes were seldom destined for anything more than a hungry tummy. But bio-products have come a long way since people first branched out into weaving hemp into clothes and pulping papyrus into scrolls. Today the line between Mother Nature and man made has never been more blurred. Animals are re-engineered into living drug factories, crops fuel our cars and now plants are increasingly being repackaged as the epitome of the synthetic world – plastic. Wheat, maize, vegetable oils, even the sugar beet are finding new life as water bottles, car fuel lines and laptops.

Bio-plastics harness the natural structures found in crops or trees, such as slightly modified forms of the chains of sugars in starch or cellulose, that share the ability to be easily reshaped that has made conventional oil based plastics so useful. Bio-materials scientists are also constantly modifying these natural structures to try and better replicate the durability and flexibility of conventional plastics.

Global business is now turning to bio-plastics for an increasing number of applications, as consumers and governments demand cleaner alternatives to petroleum based technologies and their reckless production of the greenhouse gas CO 2 .

Wheat, maize, vegetable oils, and even the are finding new life as water bottles, car fuel lines and laptops.


Worldwide players, such as DuPont and Toyota Motor Corp, are making vast investments in new technologies and processing plants with the hope of cornering a multi-billion pound industry.

Practically anything that can be found as polyethene can be found as a bioplastic. Whole range of everyday products such as cups, combs and wrappers are on the one hand there is research trying to get biological alternatives to replicate the properties of conventional plastics and on the other hand people are looking at the natural properties of these plants and trying to find an application for them. These are used in packaging to protect food.

In South Korea too there is a rapid drive to replace conventional plastic packaging with polylactic acid bio-plastics.

Bio-plastics also offer an opportunity to get a double return for the energy used in their manufacture – first as a useful item and secondly as a fuel source. The biggest advantage of such bio-materials is the reduction of CO 2

emissions in their production over petrochemical-based plastics.

Burning bio-plastics would also avoid the problems caused by them breaking down and producing methane, which is 25-times more potent as a greenhouse gas than CO 2 .

What types of bioplastic are there?

The common types of bio-plastics are based on cellulose, starch, polylactic acid (PLA), poly-3-hydroxybutyrate (PHB), and polyamide 11 (PA11). Cellulose-based plastics are usually produced from wood pulp and used to make film-based products such as wrappers and to seal in freshness in ready-made meals.

Thermoplastic starch is the most important and widely used bioplastic. Pure starch‛s ability to absorb humidity has led it to being widely used for the production of drug capsules in the pharmaceutical sector. Plasticisers, such as sorbitol and glycerine are added to make it more flexible and produce a range of different characteristics. It is commmonly derived from crops such as potatoes or maize.


Polyhydroxyalkanoate is a transparent plastic whose characteristics resemble common petrochemical-based plastics such as polyethylene and polypropylene. It can be processed for the production of conventional plastics. PLA is produced from the fermentation of starch from crops, most commonly corn starch or sugarcane into lactic acid that is then polymerised. Its blends are used in a wide range of applications including computer and mobile phone casings, foil, biodegradable medical implants, moulds, tins, cups, bottles and other packaging.

PHB is very similar to polypropylene, which is used in a wide variety of fields including packaging, ropes, bank notes and car parts. It is a transparent film, which is also biodegradable. It is prized for its thermal reistance that makes it valued for use in car fuel lines, pneumatic air brake tubing, electrical anti-termite cable sheathing and oil and gas flexible pipes and control fluid umbilicals. These are often reinforced with fibres from the kenaf plant, a member of the hibiscus family traditionally used to make paper, to increase heat resistance and durability.

At the cutting edge of bioplastic technology lie polyhydroxyalkanoate (PHA) materials. These are derived from the conversion of natural sugars and oils using microbes. They can be processed into a number of materials including moulded goods, fibre and film and are biodegradable and have even been used as water resistant coatings.

What are the benefits of bio-plastics?

Reduced CO 2 emissions.

One metric ton of bio-plastics generates between 0.8 and 3.2 fewer metric tons of carbon dioxide than one metric ton of petroleum-based plastics.

FOMA(TM) N701iECO phone made of PLA bioplastics reinforced with kenaf fibres


Rising oil prices

Despite currently costing more to produce than conventional plastics bio-plastics are becoming more viable with increasing and instability in oil prices, which are in turn triggering spikes in conventional plastic costs, illustrated in a sharp upturn two years ago. Dwindling oil supplies means that man will eventually be forced to turn to a sustainable basis for plastics.

Waste Bio-plastics reduce the amount of toxic run-off generated by the oil-based alternatives but also are more commonly biodegradable. On the other side not all bio-plastics are not biodegradable and there are a growing number of conventional plastics that can naturally break down. The downside of their biodegradability is the methane that can be released as the bio-plastics decompose is a powerful greenhouse gas.

Benefit to rural economy Prices of crops, such as maize, have risen sharply in the wake of global interest in the production of biofuels and bio-plastics, as countries across the world look for alternatives to oil to safeguard the environment and provide energy security.

Enhanced properties In some fields engineered bio-plastics are now beating oil-based alternatives at their own game. A type of Rislan PA11 has been engineered that is being used in Europe and Brazil in fuel lines to carry biofuels as it is better able to withstand the corrosive effects of biofuels than oil-based alternatives such as polyamide 12. Rislan is widely used in oilfield applications as well as automotive brake lines. Innovations in PA11 production are helping increase car passenger safety and reduce the risk of accidents by inhibiting spark ignition in the fuel lines.

A Global electronics corporation has produced a kenaf-reinforced laptop casing, made of 90% PLA, which helps reduce overheating by conducting heat better than stainless steel coupled with high temperature resistance and increased strength.


Hydrogen production in your Lab Materials Required:

2 litre plastic empty coke bottle

2 number of ½ litre plastic coke bottles with their screw-on caps

Small two-to-one air mixer valve

2 ½ metre lengths of plastic air tubing

½ cup of baking soda

HB pencil

Thermometer with centigrade scale

Procedure part 1: First we prepare the bottles and electrodes.

Step 1:

Cut the top off of the 2 litre plastic coke bottle.

Cut the bottoms off of the ½litre plastic coke bottles so they both enter completely inside 2 litre bottle.

Step 2:

Carefully cut the wood away from the pencil without cutting into the carbon graphite lead.

Break the lead in half.

Step 3: Using two 30 cm

lengths of telephone wire, remove ¼ inch insulation on one end and approximately 2 from the other end.


Tightly wrap the bare copper 2 inch end around one end of each of the carbon graphite electrodes. Encapsulate with glue.

Step 4:

Drill a hole in the top of each of the coke bottle screw-on lids.

The hole size should be the size that will allow the plastic tubing to just barely fit into the hole.

Insert the lengths of plastic aquarium air tubing. Seal around each hose with glue. Screw the caps onto the small bottles

Step 5:

Insert an electrode inside the bottom of each of the two small bottles, and glue it to the inside wall of the bottle.

Step 6:

Place the small coke bottles completely inside the large soda bottle.

Glue each small bottle in place so it will remain secure.

Procedure part 2

Now we attach the control valve, hook up the power, and label the oxygen and hydrogen tanks.

Step 7:

Install the air mixer valves in the free ends of the plastic air tubing.


Step 8:

Connect the wires coming from the electrodes to the + and – power connections on the Mini-lab Trainer.

Label the positive lead “Anode Oxygen”.

Label the negative lead “Cathode Hydrogen”.

Procedure part 3 :

We will now connect our hydrogen generator and measure the starting temperature of the water, and the actual voltage across the electrodes.

Step 9:

Mix about two litres of water with the ½ cup of soda.

Slowly pour the water into the large coke bottle, covering the tops of the small bottles. Open the air hose valves and allow the air in the small coke bottles to escape. When the small coke bottles are full of water, stop adding water.

Measure the temperature of the water in the apparatus and record the temperature.

Step 10:

Power up the Mini-lab Trainer and set to +12V. Notice that gas bubbles immediately begin to form on the electrodes in the small bottles.

Allow the process to run until the water above the electrodes has been displaced by hydrogen and oxygen in the small bottles.


Step 11:

Use your digital multimetre to directly measure the voltage between each electrode. Record the value

Procedure part 4 :

Now we will measure the current drawn through the hydrogen generator as well as the final temperature of the water. Then we will burn the gas which is produced.

Step 12:

Turn the metre to the current range and insert it in series with one of the electrode leads. Measure the amount of current required for the electrolysis process. Record the value.

Step 13:

When the small bottles are filled with

gas up to the top of the electrodes, stop the process.

At this time measure the temperature of the water in the big bottle. Record the measurement.

Record the total time of the process.

Step 14:

Light the outlet of the mixer valve. (The gas flame will not last long before the hydrogen and oxygen are used up.)


Hydrogen Production Now we will calculate the amount of energy lost, compare this to the total energy consumed, and use these values to calculate the efficiency of the electrolysis process. Step 1: Measure the amount of water remaining in the apparatus. Record the volume of remaining water. Convert your measurement into cubic centimetres

Step 2: Subtract the original temperature from the final temperature in degrees centigrade.

Multiply this temperature difference by the number of cubic centimetres of water remaining after the experiment was conducted. This is the number of calories lost due to inefficiency. Record this value.

1 calorie = 0.00116 watt-hours. Use this conversion factor to convert the lost energy to watt- hours.

Step 3: Multiply the voltage recorded across the electrodes, times the current through the electrodes, times the recorded amount of time the experiment ran. This is the total energy consumed by the experiment in watt-hours. Divide the lost energy value from Step 2 by the total energy. Multiply the result by 100% to get the percent loss of the process.

)

f s

Lost f

T T T H T V D = =

= D ×

D = = =

=

f

s

Lost 3

f

T = differencein temperature(°C) T final temperature (°C) T starting temperature (°C) H heat lost (calories) V final volume of water (cm

% 100 Lost Lost

E V I t H E

= × ×

= ×

E =total energy used (watt - hours) V =voltage (volts) l = current (amps) t = total time (hours) % Lost = percent of energy lost


Eddy Currents

The magnet falls more slowly through a metallic tube than it does through a nonmetallic tube.

When a magnet is dropped down a metallic tube, the changing magnetic field created by the falling magnet pushes electrons in the metal tube around in circular, eddy-like currents. These eddy currents have their own magnetic field that opposes the fall of the magnet. The magnet falls dramatically slower than it does in ordinary free fall in a nonmetallic tube.

Materials Required:

A cow magnet or neodymium magnet.

A nonmagnetic object, such as a pen or a pencil.

One 3 foot (90 cm) length of aluminum, copper, or brass tubing (do not use iron!) with an inner diameter larger than the cow magnet and with walls as thick as possible.

One 3 foot (90 cm) PVC or other nonmetallic tubing.

Optional: 2 thick, flat pieces of aluminum (available at hardware and home- repair stores); cardboard; masking tape; rubber bands or cord.

To do and notice

Hold the metal tube vertically. Drop the cow magnet through the tube. Then drop a nonmagnetic object, such as a pen or pencil, through the tube. Notice that the magnet takes noticeably more time to fall. Now try dropping both magnetic and nonmagnetic objects through the PVC tube.


In addition to dropping these objects through the tubes, a very simple, visible, and dramatic demonstration can be done by merely dropping the magnet between two thick, flat pieces of aluminum. The aluminum pieces should be spaced just slightly farther apart than the thickness of the magnet. A permanent spacer can easily be made with cardboard and masking tape if you don‛t want to hold the pieces apart each time. Rubber bands or cord can hold the pieces all together. The flat surfaces need to be only slightly wider than the width of the magnet itself. Thickness, however, is important. The effect will be seen even with thin pieces of aluminum, but a thickness of about 1/4 inch will produce a remarkably slow rate of fall. Allow at least a 6 inch fall.

What‛s going on?

As the magnet falls, the magnetic field around it constantly changes position. As the magnet passes through a given portion of the metal tube, this portion of the tube experiences a changing magnetic field, which induces the flow of eddy currents in an electrical conductor, such as the copper or aluminum tubing. The eddy currents create a magnetic field that exerts a force on the falling magnet. The force opposes the magnet‛s fall. As a result of this magnetic repulsion, the magnet falls much more slowly.

Eddy currents are often generated in transformers and lead to power losses. To combat this, thin, laminated strips of metal are used in the construction of power transformers, rather than making the transformer out of one solid piece of metal. The thin strips are separated by insulating glue, which confines the eddy currents to the strips. This reduces the eddy currents, thus reducing the power loss.

Eddy currents are also used to dampen unwanted oscillations in many mechanical balances. Examine your school‛s balances to see whether they have a thin metal strip that moves between two magnets.


Magnetic Pendulums Copper coils become electromagnetic swings

The current generated when one copper coil swings through a magnetic field will start a second coil swinging, showing some of the ways that electricity and magnetism interact.

Materials Required:

One 2.5 x 30 cm board, 60 cm long.

Two 2 x 4 boards, 45 cm long.

One 2.5 x 10 cm board, 24 inches 60 cm long.

One 9/16 inch (14 mm) drill bit (for cow magnet holes) and drill.

Carpenter‛s tools: Ruler, pencil, hammer or screwdriver, saw.

Nails or screws.

Magnet wire (#22 gauge or finer) for the coils.

Masking tape.

2 cow magnets (1.3 cm diameter, available at feed stores). Make sure you get the cylindrical ones with the north and south pole at the ends, not the rectangu- lar ones with north and south poles on the faces.

An electrical lead wire with alligator clips at both ends

Adult help.

Here‛s How

Use the 14 mm drill bit to drill one hole through each 2 x 4 for the cow magnets. Make four saw cuts in the 2.5 x 10 cm board. Nail or screw the boards together.


Make two coils of wire, each with at least 50 turns and an inside diameter of approximately 2.5 cm. Leave leads of approximately 3 feet (90 cm) at both ends of each coil.

Insert the magnets in the holes in the 2 x 4s. Insert the coils leads in the slots in the 2.5 x 10 cm board. Adjust the position of the coils so that they are centered right over the cow magnets. When the coils are properly positioned, bend the leads toward the middle of the top board, and tape them firmly in place near the holes. You want the coils to hang freely so that they are at the very ends of the protruding cow magnets, since this is where the magnetic field change is greatest.

Cut the leads so that the wires will reach the center of the top board with enough left over for each to be twisted together with a lead from the other coil. Scrape the insulation off the end of each wire, and twist them together as shown in the diagram to make a good electrical connection. The wires now form a continuous loop.

Tape the wire firmly to the top of the board. Make sure the wire on top of the board doesn‛t move when you swing the two coils.

Pull one coil back and then let it swing back and forth over a magnet. Notice that the second coil begins to swing.

Change the polarity of the magnet by flipping it 180 degrees and reinserting it into the 2 x 4. Swing the pendulum again and notice what happens.

Remove the tape at the top of one of the coils, and reverse the coil. Retape the leads. Swing the pendulum again and notice what happens.


Connect a clip lead from one place where the copper leads are twisted together to the other. Swing a coil and watch what happens.

What‛s going on? When you start the first coil swinging on and off the end of the first magnet, a current is induced in the coil. Since the two coils are part of the same continuous circuit, this current also flows through the second coil.

A current-carrying coil of wire behaves like a magnet. The magnetic field around the second magnet attracts or repels the second coil, setting the second coil in motion. (Alternatively, you could say that the magnet exerts a force on the current flowing through this second coil. However, the electromagnet explanation is simpler.)

When the second coil swings, it becomes a generator too - that is, a current is induced in the coil. The resulting current in the two connected loops is a result of both coils swinging through both magnetic fields.

Reversing the coil or the magnet‛s polarity changes the direction of current induced in the coil. This in turn changes the direction in which the other coil swings.

The clip lead short-circuits the coils. The electric current generated by the coil you are swinging will not flow through the second coil, so the second coil will not move.

Etcetera

You can monitor the current in the circuit by placing an ammeter (100 microam- peres) in series in the circuit. You can also monitor the voltage in the circuit by placing a voltmeter (1 volt) in parallel in the circuit: Clip it to the two twisted wire junctions. Try to observe the phase relation between the swinging coils and the voltage and current measured by the meters.


Sample Interactive Activity for Nationwide Interactive Science Olympiad

INTERNATIONAL SPACE STATION ALERT Disaster threatens a simulated mission to International Space Station (ISS).

You volunteered to figure out what‛s threatening this simulation. So go through this simulated mission activity and unfold the mystery & save this highly priced mission from devastation.

Disaster threatens a simulated mission to Inter- national Space Station unless you can figure out what‛s going wrong.

Where You Are: In the Thar desert, Rajasthan, underground in a missile testing station.

What You‛re Working On: An International Sapce Station flight simulation. Four volunteers known as Nasreen, Aman, Lata and John, known as bionauts have each been sealed into identical pods containing plants, animals and a large supply of water. The goal: Survive for six months receiving no water, food or air from the outside.

Space Station Biopods

you are Here

Mission Control


Who You Are: You are one of the project‛s volunteer “MCSyMs” - Mission Control System Monitors - the people who simulate Mission Control back on Earth. You help the bionauts adjust the life conditions in their pods - and you also monitor each bionaut‛s physical and psychological health.

When the mission Begins: The simulation has reached on its 34th day, without any problem.

The status of the simulation on Day 34: Vital signs of each pod are :-

Pod One: Nasreen . Oxygen: 21.05%. Carbon Dioxide: 0.040%. Water Temperature: 75° C degrees.

All within standard limits.

Pod Two: Aman. Oxygen: 21.02%. Carbon Dioxide: 0.043%. Water Temperature: 73° C degrees.

Nothing too alarming here.

Pod Three: Lata. Oxygen: 21.23%. Carbon Dioxide: 0.038%. Water Temperature: 76°C degrees. Oxygen and temperature are both a little high. A glance at her mission log tells you that Lata is sleeping right now, so you send her a message to read when she wakes up.

But then you look at Pod Four, John‛s pod. Oxygen: 20.51%. And even worse: Carbon Dioxide: 0.44%. Immediately you push a button: SYSTEM ALERT.

Then you grab the microphone and broadcast: “John : Alert! Your O 2 is low and CO 2 is reaching dangerous levels. What‛s going on?”


The seconds tick by agonizingly slowly. As you watch, the CO 2 level in Pod Four creeps up to 0.47%.

Then a reply comes back: from John

John says “ I‛ m okay but won‛t open the hatch. I must handle the problem on my own”.

Nasreen says “Look, we have to act fast. John‛s CO 2 is at a dangerous level. Let‛s look at John‛s pod data. If we can figure out what‛s gone wrong in his pod may be we can fix We only have about 45 minutes at this point ”.

You glance at the alarm clock. It flips over to 15:00. You turn over to the microphone and tell the team of bionauts “Attention, everyone. Lata, wake up. What‛s gone wrong with John‛s ecosystem? What could happen to make his oxygen level drop and his carbon dioxide to rise?

You keep a strict watch on the developments taking place inside the simulation. You ask all the four bionauts to give their theories on the possible reason for rise of CO 2 level in pod 4.

Hearing this, Nasreen comes up with her theory. According to this theory :John is sealed in a pod with lots of plants that converts the CO 2 he breathes out into oxygen he breathes in. But something has gone wrong with the plants & therefore there is no enough oxygen and too much CO 2 . Again, the flight simulation is carried out in a

place that was previously used as a missle testing site, so maybe the walls are radioactive. And this radiation is what‛s stopping the photosynthesis in the plants. Nasreen says that as the CO 2 level is reaching a dangerous level, so John is going to pass out soon.

To this, the commander confirms that, before the CO 2 reaches a level that is fatal for John, the emergency hatch will open up automatically. But this will shut down the experiment and to restart it again will cost about 100 crores.


Atmosphere History pod4 22.0

20.00

18.00

0.25 0.20 0.15 0.10 0.05

0 5 10 15 20 25 30 34 Day

Percent of A

tmosphere

Oxygen (O ) 2

Carbon Dioxide (Co ) 2

Trace Gases (Methane CH ) 4

Not shown : Nitrogen (appx. 78%)

Reacting to Nasreen‛s theory, John replies that he always takes care of his plants. He assures that his plants are getting enough light & plenty of nutrients and they are doing well as the other plants in rest of the pods.

Then Aman speaks up and gives his theory. He says that over population must be going on in John‛s pod. That‛s why more O 2 is consumed and lots of CO 2 is released.

To Aman‛s theory, John says that it would take over a kilogram of crayfishes, lobsters and other creatures to explain the oxygen loss in his pod. But, he says that all his oxygen breathing population seems to be normal. He gives the following database in support of his explanation

The whole history of John‛s pod is here in the project database.

The Pod 4 simulation began with an atmosphere approximating Earth‛s: 21% oxygen, 0.035% carbon dioxide, and the rest nitrogen, except for trace gases. Oxygen (O 2 ) As time goes on, photosynthesis in plants produces oxygen, which replaces the oxygen consumed by John and other aerobic creatures in the pod. Carbon Dioxide (CO 2 ) As time goes on, the pod‛s plants consume the carbon dioxide breathed out by John and other aerobic creatures in the pod.

Nitrogen - essentially an inert gas.

Trace Gases - primarily methane. Living creatures produce methane as a byproduct of digestion, especially of cellulose.

On Earth, ruminants such as cattle and termites are responsible for about a quarter of the methane released each year.


Now, on Day 34, the CO 2 level is climbing dramatically. The O 2 level has dipped correspondingly. The methane level has also climbed steeply, almost parallel with the increase in carbon dioxide.

Lata, who got up from sleep short while ago, comes up with her theory. She says that John‛s pod got a little off balance as he started wor- rying. It raised his metabolism and so he is consuming more oxygen.

She asks John to calm down first.

Finally John comes up with his theory. He says that something must be undergoing oxidation, that is, some metal in his pod must be undergoing rusting somewhere in his pod, that is why the O 2 level is decreasing.

Four bionauts with four differnt theories. They go through the database presented by John. Then they decide to go on a virtual tour of pod 4 and examine everything in it. They look for clues and move to every part of the pod.

Inside John‛s pod :

That is the garden area. There is big pond with the deck in the middle. Lots of plants are there which - looks like a jungle

This is the living area – There is bunk in the middle, and the desk is on the left. Mini-kitchen over to the right, and the table next to it. John says he don‛t see anything unusual there.

Garden Area Pod Four

Living area Pod Four


This is the storage locker. This is where the consumable supplies of food, of six months are stored. They are all wrapped in card board and stored in wooden crates.

Now you look at the current carbon dioxide level in Pod Four. It is now 0.48%.

“We don‛t have much time left,” you say. “At 0.5%, it‛s all over.”

International Space Station Alert

The carbon dioxide level in Pod 4 slides up to 0.49% It‛s time to make a quick decision.

What‛s going wrong in John‛s Pod Four? Plants are not producing enough oxygen........

John is stressed, and ................

Somewhere in John‛s pod.......

Storage Locker Pod Four


You direct the bionauts to immediately workout on the possible reasons given in their theories.

The bionauts immediately start working out on all the reasons they gave in their theory and finds-

John‛s plants are diseased-------- They looks for any diseased plants in John‛s pod but finds that all the plants are perfectly healthy.

Radioactivity effecting John‛s plants ------- they find that there are no high levels of radiation in the pod and that John‛s plants are perfectly healthy.

Over population -------- John catches all the creatures he can find and puts them in freezer. Despite this the CO 2 level continues to rise.

Hyperventilation--------- John calms down, his metabolic rate drops to a very low level. Despite this the CO 2 level continues to rise.

Rusting is consuming more O 2 -------- But John still can‛t find anything rusting in his pod

Finally, the commander steps in and commands the bionauts to shut all the air- tight doors to their bedrooms and storage lockers. And little by little the carbon dioxide level in the main living area of John‛s pod creeps back down to normal.

The bionauts find two colonies of termites hidden in the wooden crates in John‛s storage locker, and some other bugs had got into the foodstuffs. Over three kg of insects were hidden in the food supplies !

In the mean time, inside the mission control, you were investigating the theories given by the bionauts, and the investigation shows that

Although the simulation was carried out in an old missile testing site, the radiation levels were very low and it did not affect the plants and so they were perfectly healthy and not diseased.


Population of the creatures in John‛s tank were at normal levels.

Investigation proved that although anxiety can indeed raise oxygen consumption, but it was not a significant factor in this case, because the O 2

level was decreasing at a faster rate.

Rusting is a type of oxidation. Investigation shows that rusting did not consume significant oxygen in John‛s pod.

Finally, before the CO 2 level in Pod 4 could reach 0.5%, the mystery was solved and the simulation could be saved from destruction.

Now answer these Questions :

1. Where is the simulation located? (a) On International Space Station (b) Underground in Thar desert (c) Inside the pod (d) In space

2. Why the simultation will destroy when the CO 2 level reaches 0.5%? (a) Because it will cause extensive heating. (b) To save the bionauts as prolonged exposure to CO 2 at this level is

potentially dangerous. (c) Both (a) and (b) (d) None of the above

3. Which do you think is the most significant cause for rise in CO 2 level in pod 4?

(a) Over population of creatures (b) Radiation effect (c) Anxiety (d) Colony of termites and bugs.

4. Why do you think the cause you chose for rise in CO 2 level in pod 4 is most significant?

(a) Because overcrowded population means more consumption of O 2 & more release of CO 2

(b) Radiation adversely effects photosynthesis in plants. (c) Anxiety increases CO 2

(d) Termites and bugs produces significant CO 2 & methane gas.


For centuries, debating the nature of consciousness was the exclusive purview of philosophers. But if the recent torrent of books on the topic is any indication, a shift has taken place: Scientists are getting into the game.

Has the nature of consciousness finally shifted from a philosophical question to a scientific one that can be solved by doing experiments? The answer, as with any related to this topic, depends on whom you ask. But scientific interest in this slippery, age-old question seems to be gathering momentum. So far, however, although theories abound, hard data are sparse.

The discourse on consciousness has been hugely influenced by René Descartes, the French philosopher who in the mid-17th century declared that body and mind are made of different stuff entirely. It must be so, Descartes concluded, because the body exists in both time and space, whereas the mind has no spatial dimension.

Recent scientifically oriented accounts of consciousness generally reject Descartes‛s solution; most prefer to treat body and mind as different aspects of the same thing. In this view, consciousness emerges from the properties and organization of neurons in the brain. But how ? And how can scientists, with their devotion to objective observation and measurement, gain access to the inherently private and subjective realm of consciousness?

Some insights have come from examining neurological patients whose injuries have altered their consciousness. Damage to certain evolutionarily ancient structures in the brainstem robs people of consciousness entirely, leaving them in a coma or a persistent vegetative state. Although these regions may be a master switch for consciousness, they are unlikely to be its sole source. Different aspects of consciousness are probably generated in different brain regions. Damage to visual areas of the cerebral cortex, for example, can produce strange deficits limited to visual awareness. One extensively studied patient, known as D.F., is unable to identify shapes or determine the orientation of a thin slot in a vertical disk. Yet when asked to pick up a card and slide

What Is the Biological Basis of Consciousness?


it through the slot, she does so easily. At some level, D.F. must know the orientation of the slot to be able to do this, but she seems not to know she knows.

Cleverly designed experiments can produce similar dissociations of unconscious and conscious knowledge in people without neurological damage. And researchers hope that scanning the brains of subjects engaged in such tasks will reveal clues about the neural activity required for conscious awareness. Work with monkeys also may elucidate some aspects of consciousness, particularly visual awareness. One experimental approach is to present a monkey with an optical illusion that creates a “bistable percept,” looking like one thing one moment and another the next. (The orientation-flipping Necker cube is a well-known example.) Monkeys can be trained to indicate which version they perceive. At the same time, researchers hunt for neurons that track the monkey‛s perception, in hopes that these neurons will lead them to the neural systems involved in conscious visual awareness and ultimately to an explanation of how a particular pattern of photons hitting the retina produces the experience of seeing, say, a rose.

Experiments under way at present generally address only pieces of the consciousness puzzle, and very few directly address the most enigmatic aspect of the conscious human mind: the sense of self. Yet the experimental work has begun, and if the results don‛t provide a blinding insight into how consciousness arises from tangles of neurons, they should at least refine the next round of questions.

Ultimately, scientists would like to understand not just the biological basis of consciousness but also why it exists. What selection pressure led to its development, and how many of our fellow creatures share it? Some researchers suspect that consciousness is not unique to humans, but of course much depends on how the term is defined. Biological markers for consciousness might help settle the matter and shed light on how consciousness develops early in life. Such markers could also inform medical decisions about loved ones who are in an unresponsive state.

Until fairly recently, tackling the subject of consciousness was a dubious career move for any scientist without tenure (and perhaps a Nobel Prize already in the bag). Fortunately, more young researchers are now joining the fray. The unanswered questions should keep them—and the printing presses— busy for many years to come.

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