Inventions and DiscoveriesElectromagnetic waves .................................................................. 3 The Wireless .................................................................................. 5 Television ..................................................................................... 12 Camera ......................................................................................... 15 Electricity .................................................................................... 17 Blood groups ............................................................................... 19 Printing ....................................................................................... 21 Bacteria ........................................................................................ 23 Cells ............................................................................................. 28 Antibiotics ................................................................................... 30 Petroleum ..................................................................................... 32 Oxygen ........................................................................................ 34 Refrigerator .................................................................................. 39 Pencil and Pen ............................................................................. 43 Computer ..................................................................................... 44 Electric lamp ................................................................................ 47 Automobiles ................................................................................ 50 Electric battery ............................................................................. 52 Loudspeaker ................................................................................ 54 Microphone .................................................................................. 56 Microwave oven .......................................................................... 58 Airplane ....................................................................................... 64 Laser ............................................................................................ 67 Vaccination .................................................................................. 70 Clocks and watches ..................................................................... 72 Wheel ........................................................................................... 74 Glass ............................................................................................ 80 Portland Cement .......................................................................... 82 Bicycle ......................................................................................... 84 .................................................................................................... 86 Iron .............................................................................................. 87 Toothpaste .................................................................................... 90 Thermometer ............................................................................... 91 Soap ............................................................................................. 94 Cinema ......................................................................................... 96 Tape recorder ............................................................................... 98

Electromagnetic wavesIn 1831, a British scientist Michael Faraday discovered that changing electric current in a coil of wire can induce a current in a nearby coil. The current induced in the second coil is proportional to its number of turns. James Clerk Maxwell, a compatriot of Faraday, was a theoretician. A theoretician is a scientist who does not work with instruments or devices rather he dabbles with mathematical formulations of observations. In 1865, as a result of his studies, he discovered the mechanism of interaction between electricity and magnetism. He suggested that a change in electric current can start a train of waves, the electromagnetic waves, that radiate into space just like light waves. According to him, the only difference between a light wave and an electromagnetic wave is a characteristic of waves-the wavelength. Not all scientists accepted Maxwell's ideas; after all there was no proof of the existence of electromagnetic waves. The Berlin Academy of Science offered a prize to anyone who could prove that electromagnetic waves exist. In 1879, Heinrich Rudolf Hertz, a German scientist took the challenge in 1886.

Hertz knew the work of Faraday. He devised a simple experimental setup made up of two devices. The first device had two coils placed near one other. He passed electric current from a battery into the first wire coil. The second coil had many more turns than the first coil. As per the discovery of Faraday the voltage developed in the second coil was much higher than that of the battery. This current was led to a pair of capacitors. (A capacitor is a pair of metal plates that can accumlate electricity until they can hold no more.) As soon as the capacitors were charged to their capacity they discharged by sending an electric spark between two small

metallic balls. The second device had similar balls connected to a wire that was bent into circle and it was placed at a distance from the first device. He demonstrated that whenever an electric spark was generated in the first device a spark can be observed in the second device also, even though the two were not connected through any wires. The only way these two devices could communicate with one another was through electromagnetic waves. This proved Maxwell's ideas.

The WirelessAfter it was discovered that out of various electromagnetic waves, only those having wavelength more than a meter could be used for remote wireless communication. For example, light waves could not be used for communication because most common objects obstruct them. They cannot pass through a wall of a building. Electromagnetic waves that can go across walls and hence can be used for long distance communication are called radio waves. They can be transmitted without wires or through wires, just like electricity. It was also found that radio waves having nearly equal wavelength interfere with one another, if received simultaneously at a particular location. Therefore radio waves of a particular wavelength can be used to communicate to people at a particular location only if nobody else is transmitting radio waves of the same wavelength. Many inventors in different countries tried simultaneously to invent a communication device using radio waves. For example, in 1893 a scientist born in Hungary, Nikola Tesla, made the first public demonstration of such a system. He described and demonstrated in detail the principles of radio communication. The apparatus that he used contained almost all the elements that were used later. In 1894, an Indian scientist, Jagdish Chandra Basu, also demonstrated publicly the use of electromagnetic waves in Kolkata. He was not interested in patenting his work, so his work is not recognized internationally. In the same year a British physicist, Sir Oliver Lodge, demonstrated the reception of Morse code signalling using radio waves with the help of a detecting device -- a coherer. This coherer was a tube filled with iron filings. It was invented by an Italian, Temistocle Calzecchi-Onesti, in 1884 to drain off electricity

during lightening. Edouard Branly of France and Alexander Popov of Russia later produced improved versions of the coherer. Many people claim that Popov was the first person to develop a practical communication system.

The inventor who is generally recognized as the inventor of wireless telegraph is Gugliemo Marconi, an Italian. He began by building an apparatus similar to the one used by Hertz. He added a telegraph key to the spark generator, so that he could send signals corresponding to the dots and dashes of the Morse code. To check whether it was a practical communication device Marconi moved his appratus outdoors to try its transmission- reception over long distances. During these experiments he made a lucky discovery: When one terminal of the generator and receiver were connected to the ground, communication was possible across longer distances. He also discovered the need for antenna (aerials); they transmit signals from the transmitter to space and from space to the receiver equipment. By 1895, Marconi had developed a device with which he could send signals across a few kilometers. Marconi got a patent for his inventions in 1896, the world’s first patent for “radio communication”. After patenting his invention Marconi established a company called Marconi’s Wireless Telegraph Company in London. In 1898 Marconi successfully transmitted signals across the English Channel. The most dramatic use of wireless was for rescuing ships in distress. Several ships were equipped with wireless telegraphy equipment, they could send or receive distress messages from ships sailing nearby.

Till the beginning of the twentieth century, wireless communication was limited to telegraphy. Many people dreamt of wireless telephony at that time, but the technology to achieve that was not available.

Sound waves are continuous waves, their frequency is much lower than that of electromagnetic waves. (Frequency is another characeristic of a wave very closely related to its wavelength). For wireless communication a sound signal has to be converted into a radio wave. It was soon found that any electric signal can be carried on a radio wave (modulation of electromagnetic waves). All that was necessary for wireless communication of sound was an equipment that could generate electric current having frequency of the radio waves. Several inventors invented such devices. The most notable amongst them was Nikola Tesla, who invented the alternating current and Ernst Alexanderson who built the first alternator that could produce alternating current having frequency about 50 thousand cycles.

Although the exact time when the human voice was first transmitted by radio is debateable, it is claimed that speech was first transmitted across the American continent, from New York City to San Francisco, in 1915. During the First World War radiotelephony between ground and aircraft was also tried. The first ship-to-shore two way radio conversation occurred in 1922. However, a public radiotelephone service for people at sea was inaugurated in 1929. At that time telephone contact could be made only with ships within 2000 km of shore. Today every large ship wherever it may be on the globe can be contacted using wireless equipment.

The TelephoneThe success of telegraph by 1874 enthused several young minds in Europe and America. People started dreaming about the possibility of talking through wires, but no body knew how voice could be converted into electric current and vice versa. One such young man was Alexander Graham Bell. His father was a speech teacher who had worked out a system called visible speech. This system used symbols to represent all of the sounds that people make while speaking. He hoped to use this "sound alphabet" for teaching the art of speaking to deaf people. Deaf people have trouble speaking clearly because they cannot hear what they are saying. Young Alexander Bell was fascinated by his father's work. When he was sixteen years old his father challenged him to build a machine that could make speech sounds. He therefore studied the larynx, the voice-producing organ, of a lamb. Soon he developed a voice box that made different sounds using levers. He also studied how the mouth changes shape while making vowel sounds. From books he came to know that a learned German scientist, Herman von Helmholz, had used electrically operated tuning forks to reproduce certain sounds of human speech.

Graham Bell started his efforts in the direction of the invention of telephone by attempting to develop a "harmonic telegraph", a device that would allow several telegraph operators to send messages on the same wire at the same time. Thus he developed an idea for the telephone. By October 1874, Bell's research had progressed to the extent that he could inform his future father-in-law, Gardiner Greene Hubbard, about the possibility of a multiple telegraph. Hubbard resented the absolute control on telegraph services exerted by the Western Union Telegraph Company in USA at that time. He

instantly saw in the Bell's efforts a potential for breaking such a monopoly, so he gave Bell the financial backing he needed. Bell proceeded with his work on the multiple telegraph. But he did not reveal to Hubbard that he and Thomas Watson, a young electrician whose services he had enlisted, were also exploring an idea that had occurred to him that summer. The idea was to develop a device that would transmit speech electrically. They were working on a device that used steel reeds that could be set in vibration by electromagnets. One day Watson tightened an adjustment screw of his device a little too much. This prevented the reed from vibrating, so he plucked the reed to try to set it in motion again. Bell sitting in another room next to his instruments heard a sound coming from the reeds in the device near him. He rushed to Watson to find how it happened. What excited him the most was the fact the sound was not produced by an on and off electric current as was the case with electric telegraph it was a continuous sound. Soon thereafter Bell experimented with vibrating membranes instead of reeds. He was prompted to do so by his knowledge of the human ear. Within a few weeks he was successful in transmitting the sounds of human voice through system that was composed of a microphone and a speaker. The microphone was like a funnel. One end open the other end pointing to a membrane connected to a rotor that had to follow the vibrations of the membrane. This vibrating rotor was connected to a coil to induce an electric current that could reproduce the voice sent into the funnel. Bell's microphone changed sound waves into an electric current whose intensity changed quickly. The electric current can travel much faster and it is easier to transmit it across long distances than sound.

Graham Bell was not the only person who was trying on such an idea. Another American inventor

Elisha Gray was working on similar lines. In fact he also smelt success just at the same time. But on February 14 1876 when Bell's father in law filed an application for the preliminary patent of Bell's invention, Elisha Gray was just a few hours too late. Nevertheless Bell had to face many problems similar to the ones faced by many other inventors at that time. Nobody was initially interested in his invention. When he offered his patent for 100,000 American Dollars, the response was "What shall we do with a toy like that?" This occurred in 1877. The telephone invented by Graham Bell was not immediately accepted for conversation, it was more commonly used to send and listen to music. But after some improvements it became popular for conversations.

TelevisionTelevision was not invented by one inventor, many inventors from various parts of the world contributed. Therefore, its story is to be told slightly differently.

Television, in a way, is an extension of our sense of vision. The process of televising a visual consists of three steps. Seeing it through a camera; transmitting it to remote places and finally producing its image on the screen of a TV. The camera used for television is different from a photography camera. A photography camera cannot be used for televising because it does not produce any electrical signals. Finding a method to convert the image of a visual into a electric current was indeed the first challenge for the potential inventors of television. The discovery that led to the invention of television was the discovery of the chemical element “Selenium”. A Swedish scientist, Jacob Berzelius, discovered it in the early nineteenth century. It produces an electric current when light falls on it and is therefore called a photosensitive element (photo = light). This discovery led to invention of several devices that could convert an image into an electric current and reproduce the image. One such device was invented by a German engineer, Paul Nipkow, in 1884. This device “the Nipkow’s disk” was an electromechanical device, and hence was not very successful.

For the later developments it was necessary to know what exactly is an electric current. Nobody knew it till 1897! Electric current became known to be a flow of electrons after an English scientist, J.J. Thomson, discovered electrons -- the tiny negatively charged particles in atoms. The invention of cathode ray tube (CRT) by a German scientist, Karl

Ferdinand Braun, was perhaps crucial for the development of an electronic television. In 1897, after electrons had been “discovered” Braun, like many other scientists of the day was intrigued. Braun discovered that a stream of electrons emanating from a negatively charged electrode (cathode) inside a glass tube from which most of the air had been removed—a cathode ray tube (CRT)—could be focused to a point at the end of the tube. If the end of the tube were coated with a fluorescent material, it would glow wherever the stream of electrons hit it. Braun also used a magnet outside the tube, which interacted with the electrons in the beam to move it back and forth. By moving the magnet, he could trace patterns on the screen. Braun also used a magnet outside the tube, which interacted with the electrons in the beam to move it back and forth. By moving the magnet, he could trace patterns on the screen.

It was later discovered that an image projected/focussed on the screen of a CRT can be scanned, read like the text written on a paper, by moving its beam over each point of the image. Cathode rays were moved using electromagnets because it was already known that the strength of an electromagnet can be varied by changing the electric current flowing through it. Scanning an image to produce electric signal was therefore now possible. Inventors tried coating the screen of a CRT with selenium and found that the characterstics of electric current produced depends on the image focussed on the screen. The first electronic device that was close to the modern TV was invented by a Russian inventor, Vladimir

Zworykin, in 1923. He called it ‘iconoscope’, it laid the foundations for early television cameras.

However, the inventor who is most often credited for the invention of television is John Logie Baird, a Scottish engineer. He achieved the transmission of simple face shapes in 1924 using Nipkow’s disc. Baird demonstrated 'television' publicly in London on March 25, 1925.

The details of a scene in front of the camera can be transmitted either through wireless transmitters ( very similar to those used for broadcasting sounds) or through a cable—like telephone. An image of the scene can be produced on the screen of a television set by feeding into its CRT the electrical signal received. The main difference between the picture tube of a television set and that used in a television camera is the coating on their screens, while a photoconducting material, say, selenium, is used for coating the screen of the CRT inside a camera, chemicals known as phosphors were (and are still) used on the screen of a TV. A small dot of phosphor produces a dot of light when cathode rays fall on it. This light lasts only a fraction of second. Such light dots produce a transient image on the screen. A sequence of such transient images produces a movie.

CameraThe earliest form of a camera is often called "Camera Obscura". A Chinese philosopher Mo-Ti (5th century BC) was perhaps the first person to mention this type of device. He formally recorded the creation of an inverted image formed by light rays passing through a pinhole into a darkened room. He called this darkened room a "collecting place" or the "locked treasure room." Aristotle (384-322 BC), a famous Greek philosopher, also understood the optical principle of the "camera obscura". He viewed the crescent shape of a partially eclipsed sun projected on the ground through the holes in a sieve, and the gaps between leaves of a plane tree.

The earliest "Camera Obscuras" were large rooms that were used to observe a solar eclipse. A convex lens was used into the aperture in the 16th century to improve the image quality; a mirror was added to reflect the image down onto a viewing surface. This device was often used as an aid for drawing for artists. Soon thereafter, in 1807, another kind of camera known as "Camera Lucida" was invented. No darkroom was needed for this kind of camera. The paper was laid flat on the drawing board, and the artist would look through a lens containing the prism, so that he could see both the paper and a faint image of the subject to be drawn. He would then fill in the image.

Obtaining a direct recording of an image that did not require the skills of an artist was not possible till certain chemical substances that changed their properties when they are exposed to light became known. A German scientist discovered in 1727 that if he mixes three chemicals: chalk, nitric acid, and silver in a flask, the side of the flask facing sunlight gets darkened. In 1800, a scientist from England, Thomas Wedgwood, made the first "sun pictures" by

placing opaque objects on leather treated with a chemical called silver nitrate. However, these pictures survived only under candles light, under any stronger source of light they detoriated very fast. It was not until 1826 when a French scientist Nicéphore Niépce, combined the camera obscura with photosensitive paper that it was possible to obtain a permanent image. Soon thereafter, in 1834, another English scientist, Henry Fox Talbot, used paper impregnated with silver nitrate or silver chloride. When exposed in a camera, this paper turned black where light struck it, creating a negative image of the subject. This was made permanent by fixing with hypo. The images so obtained were of course only black and white. (The story of development of photography is very aptly detailed on the website http://www.scphoto.com/html/history.html.)

These early development led to many other discoveries and inventions that made it possible for newspapers to carry photographs by 1880. Way back in 1900 one could purchase a camera and shoot pictures using photography films produced by the company Eastman Kodak.

ElectricityA Greek philosopher Thales of Miletus, who lived about 600 BC, is said to have discovered that amber acquires a power to attract light objects when rubbed. Another Greek philosopher, Theophrastus, in a treatise written about three centuries later, told that some other substances also possess this power. Similarly, ancient Greeks as well as Chinese knew magnets. But, it was not until AD 1600, when an English physician William Gilbert studied both of them in detail and his observations were available in printed form, that the facts about electricity and magnetism became widely known. Gilbert was the first person to apply the term electric (Greek elektron, "amber") to the force that such substances exert after rubbing. He also distinguished between magnetic and electric action.

The first machine for producing an electric charge was invented in 1672 by a German scientist Otto von Guericke. It consisted of a sulfur sphere turned by a crank on which a charge was induced when the hand was held against it. The French scientist Charles Francois de Cisternay Du Fay was the first to discover that there are two different types of electric charge: positive and negative. The earliest device to store electric charge, the Leyden jar, was invented in 1745 at the University of Leiden in the Netherlands. It consisted of a glass bottle with separate coatings of tinfoil on the inside and outside. One sensed a violent shock by touching both coatings of the foil simultaneously.

Benjamin Franklin, an American scientist, spent much time to study electricity. Through his famous kite experiment he discovered that the atmospheric electricity that causes the phenomena of lightning and thunder is identical with the electrostatic charge on a Leyden jar. Franklin suggested that electricity is a "fluid" existing in all matter, and that

its effects can be explained by excesses and shortages of this fluid.

Alessandro Volta, an Italian scientist invented the first device capable of producing an electric current (electricity), a battery. He found that if pieces of two different metals were separated with a cardboard disk soaked in brine (salt solution), an electric current flows through the wires connected to these metal pieces. In 1800, he announced a new electrical device, the Voltaic Pile. This device was made of alternating disks of zinc and copper with each pair separated by brine soaked cloth. This was the first battery.

In 1831 Michael Faraday, a British scientist discovered the electromagnetic induction. This is a method for producing a steady electric current. Faraday attached two wires through a sliding contact to a copper disc. By rotating the disc between the poles of a horseshoe magnet he obtained a continuous direct current. This was the first electric generator; it led to the establishment of the first electric power station in 1888.

Blood groupsTe true nature and function of blood have been shrouded in mystery ever since the beginning of history. Using human blood to treat disease and trauma had its beginnings in 1667 in France, when Jean-Baptiste Denis documented a direct human blood transfusion. This was a scant forty years after William Harvey discovered the circulatory system. These early direct donor-to-patient transfusions were, however, frequently disastrous because it was not possible to predict donor-recipient blood type compatibility.

Experiments with blood transfusions, the transfer of blood or blood components into a person's blood stream, have been carried out for hundreds of years. Many patients died because of blood transfusions. Thus while in 1818, when James Blundell transfused blood to a woman from her husband and it worked. But other patients died from transfusions. It was decades later when a German named Leonard Landois learned why blood mixing can be fatal: Sometimes it makes red blood cells clump and explode.

In 1901-1903 Landsteiner pointed out that a similar reaction may occur when the blood of one human individual is transfused, not with the blood of another animal, but with that of another human being, and that this might be the cause of shock, jaundice, and haemoglobinuria that had followed some earlier attempts at blood transfusions.

His suggestions, however, received little attention until, in 1909, he classified the bloods of human beings into three blood groups A, B, and C. These eventually became known as A, B, and O. The rarer group AB was not discovered until the following year by two of Landsteiner's pupils. These groups are now well-known as A, B, AB, and O groups.

Landsteiner showed that transfusions between individuals of groups A or B do not result in the destruction of new blood cells and that this catastrophe occurs only when a person is transfused with the blood of a person belonging to a different group.

Karl Landsteiner's work made it possible to determine blood types and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930. Later in 1940 Landsteiner and Weiner made observations which laid the foundations of our knowledge about the remaining major blood group - the Rhesus system. Once reliable tests for Rhesus grouping had been established, deaths due to blood transfusion became rare.

Printing Written language is unquestionably one of the most important human achievements therefore the ability to reproduce written materials quickly and efficiently ranks not far behind. Only when written works could be duplicated in quantities and speeds exceeding those achievable through laborious handwritten copies did writing become a medium for the widespread dissemination of knowledge—the more copies of material available, the more people who have access to them, the more likely the spread of literacy. The challenge, particularly in civilizations with large, complex systems of writing, was to develop a method for quickly and efficiently arranging those symbols, using the arrangement to create printed material, then re-arranging the symbols for further use. Chinese printers were the first to structure printing in a way that hinted at mass-production in the 8th century. They used wooden blocks with characters carved into them, which were then inked and stamped on paper. Extending the Chinese monopoly on printing, in the 11th century Pi Sheng created a primitive form of moveable type (made of wood), which allowed for the letters to be rearranged. In a neighboring country Korea, moveable metal type was tried in the early 15th century but it was not very successful due to the large number of characters in Korean script. In Europe printing developed a bit later. Till the beginning of the 15th century, they followed the method introduced by Chinese -- block printing.

As the methods for casting metals became known, the invention of a machine to print became possible. An innovator in Germany, Johann Gutenberg spent over ten-years developing the western-style moveable type. He then developed a method using lead and tin alloys to mold moving type for individual letters of the Roman

script. He also invented a machine, the printing press that was based on the design of presses used by farmers to make olive oil. The first printing press used a heavy screw to force a printing block against the paper below and the ink used was a mixture of turpentine, lampblack and linseed oil. Invented by 1450 such a printing press made the mass publication and circulation of literature easy and economical. In the later models, as machines became more popular, inking was carried out by rollers. These rollers would pass over the face of the type and move out of the way onto a separate ink-bed to pick up a fresh film of ink. A sheet of paper was slid against a hinged plate, which was rapidly pressed onto the type and then swung back, allowing it to be removed and the next sheet inserted in its place.

BacteriaBacteria are the most abundant of all organisms. They are ubiquitous in soil and water. Bacteria consist of only a single cell, but they are an amazingly complex and fascinating group of creatures. When most people think of bacteria, they think of disease-causing organisms. But that is strictly not true. Several kinds of bacteria are extremely helpful to us, they help us make medicines or cook food.

Antony van Leeuwenhoek, the man who discovered bacteria, was neither a physician nor a university professor but a Dutch draper and part-time janitor who liked to look at things under a microscope. Leeuwenhoek came from a family of tradesmen, had no fortune, received no higher education or university degrees, and knew no languages other than his native Dutch. This would have been enough to exclude him from the scientific community of his time completely. Yet with skill, diligence, an endless curiosity, and an open mind free of the scientific dogma of his day, Leeuwenhoek succeeded in making some of the most important discoveries in the history of biology. It was he who discovered bacteria.

Leeuwenhoek's skill at grinding lenses, together with his naturally acute eyesight and great care in adjusting the lighting where he worked, enabled him to build microscopes that magnified over 200 times, with clearer and brighter images than any of his colleagues could achieve. What further distinguished him was his curiosity to observe almost anything that could be placed under his lenses, and his care in describing what he saw. Although he himself could not draw well, he hired an illustrator to prepare drawings of the things he saw, to accompany his written descriptions. Most of

his descriptions of microorganisms are instantly recognizable.

In 1673, Leeuwenhoek began writing letters to the newly formed Royal Society of London, describing what he had seen with his microscopes -- his first letter contained some observations on the stings of bees. For the next fifty years he corresponded with the Royal Society; his letters, written in Dutch, were translated into English or Latin and printed in the Philosophical Transactions of the Royal Society, and often reprinted separately.

RocketRocket is an indispensable tool in the exploration of space. Today's rockets are remarkable collections of human ingenuity that have their roots in the science and technology of the past.

One of the first devices to successfully employ the principles essential to rocket flight was a wooden bird. The writings of Aulus Gellius, a Roman, tell a story of a Greek named Archytas who lived in the city of Tarentum, now a part of southern Italy. Somewhere around the year 400 B.C., Archytas mystified and amused the citizens of Tarentum by flying a pigeon made of wood. Escaping steam propelled the bird suspended on wires. The pigeon used the action-reaction principle, which was not stated as a scientific law until the 17th century. About three hundred years after the pigeon, another Greek, Hero of Alexandria, invented a similar rocket-like device called an aeolipile. It, too, used steam as a propellant.

Hero mounted a sphere on top of a water kettle. A fire below the kettle turned the water into steam, and the gas traveled through pipes to the sphere. Two L-shaped tubes on opposite sides of the sphere allowed the gas to escape, and in doing so gave a thrust to the sphere that caused it to rotate.

No one is really sure when the first true rocket was built. Stories of early rocket-like devices appear sporadically through the historical records of various cultures. Perhaps the first true rockets were accidents. In the first century A.D., the Chinese reportedly had a simple form of gunpowder made from saltpeter, sulfur, and charcoal dust. To create explosions during religious festivals, they filled bamboo tubes with a mixture and tossed them into fires. Perhaps some of those tubes failed to explode and instead skittered out of the fires, propelled by

the gases and sparks produced by the burning gunpowder.

Chinese began experimenting with the gunpowder filled tubes. At some point, they attached bamboo tubes to arrows and launched them with bows. Soon they discovered that these gunpowder tubes could launch themselves just by the power produced from the escaping gas. The true rocket was born.

The date reporting the first use of true rockets was in 1232. At this time, the Chinese and the Mongols were at war with each other. During the battle of Kai-Keng, the Chinese repelled the Mongol invaders by a barrage of "arrows of flying fire." These fire-arrows were a simple form of a solid-propellant rocket. A tube, capped at one end, contained gunpowder. The other end was left open and the tube was attached to a long stick. When the powder was ignited, the rapid burning of the powder produced fire, smoke, and gas that escaped out the open end and produced a thrust. The stick acted as a simple guidance system that kept the rocket headed in one general direction as it flew through the air. Although one may not be sure how effective these arrows of flying fire were as weapons of destruction, but their psychological effects on the Mongols was formidable.

Following the battle of Kai-Keng, the Mongols produced rockets of their own and may have been responsible for the spread of rockets to Europe. All through the 13th to the 15th centuries there were reports of many rocket experiments. In England, a monk named Roger Bacon worked on improved forms of gunpowder that greatly increased the range of rockets. In France, Jean Froissart found that more accurate flights could be achieved by launching rockets through tubes. Froissart's idea was the forerunner of the modern bazooka. Joanes de Fontana of Italy designed a surface-running

rocket-powered torpedo for setting enemy ships on fire.

By the 16th century rockets were mainly used for fireworks displays, and a German fireworks maker, Johann Schmidlap, invented the "step rocket," a multi-staged vehicle for lifting fireworks to higher altitudes. A large sky rocket (first stage) carried a smaller sky rocket (second stage). When the large rocket burned out, the smaller one continued to a higher altitude before showering the sky with glowing cinders. Schmidlap's idea is basic to all rockets today that go into outer space.

Nearly all uses up to this time were for warfare or fireworks, but there is an interesting old Chinese legend that reported the use of rockets as a means of transportation. With the help of many assistants, a lesser-known Chinese official named Wan-Hu assembled a rocket- powered flying chair. Attached to the chair were two large kites, and fixed to the kites were forty- seven fire-arrow rockets.

During the early introduction of rockets to Europe, they were used only as weapons. Enemy troops in India repulsed the British with rockets. During the 19th century, rocket enthusiasts and inventors began to appear in almost every country. By the end of the 19th century, soldiers, sailors, practical and not so practical inventors got interested in rocketry. Skillful theorists, like Konstantian Tsiolkovsky in USSR, studied the science behind rocketry. They also examined the possibility of space travel. Three persons were particularly significant in the transition from the small rockets of the 19th century to the giant rockets of today. They were: Konstantin Tsiolkovsky from Russia, Robert Goddard from the United States, and Hermann Oberth from Germany.

CellsMost cells are too small, they cannot be observed with the naked eye. It is for this reason that the existence of cells escaped notice until scientists first learned to harness the magnifying power of lenses in the second half of the seventeenth century, that is the invention of the microscope. A Dutch clothing dealer named Antonie van Leeuwenhoek invented the single-lens microscopes. Gazing into the lens of these microscopes, he discovered single-celled organisms, which he called "animalcules" and which, today, we call bacteria and protists.

Englishman Robert Hooke expanded on Leeuwenhoek’s observations with the newly developed compound microscope, which uses two or more aligned lenses to increase magnification while reducing blurring. When Hooke turned the microscope on a piece of cork, he noticed that the tiny, boxlike compartments of the wood resembled the cells of a monastery. The term 'cell' was born.

As microscope technology improved, scientists were able to study cells in ever-greater detail. Hooke had no way to tell if cells were living things, but later researchers who could see the nucleus and the swirling motion of the cytoplasm were convinced that cells were indeed alive. By 1839, enough evidence had accumulated for German biologists Matthias Schleiden and Theodore Schwann to proclaim that cells are “the elementary particles of all biological organisms. But many scientists still did

not believe that cells arose from other cells until 1855, when a famous German scientist Rudolph Virchow pronounced, "All cells come from cells." Nearly 200 years after the discovery of cells, the observations of Virchow, Schleiden, and Schwann established the cell theory. According to this theory: All living things are made of cells and all cells arise from preexisting cells.

AntibioticsThe use of antibiotics is often considered one of the wonders of the modern world. It has had dramatic effects on the practice of medicine, the pharmaceutical industry, and microbiology. Prior to the discovery of antibiotics, the treatment of infectious diseases was not very scientific. Various types of antimicrobial agents, including extracts of plants, fungi, and lichens, were employed for thousands of years in primitive populations without any scientific knowledge of what was being used. Even in the early part of the twentieth century, therapy for infectious diseases was based essentially on patient isolation and chicken soup.

The search for antibiotics began in the late 1800s, with the growing acceptance of the germ theory of disease, a theory, which linked bacteria and other microbes to the causation of a variety of ailments. As a result, scientists began to devote time to searching for drugs that would kill these disease-causing bacteria. The goal of such research was to find so-called “magic bullets” that would destroy microbes without toxicity to the person taking the drug.

One of the earliest areas of scientific exploration in this field was whether harmless bacteria could treat diseases caused by pathogenic strains of bacteria. By the late 19th century there were a few notable breakthroughs. In 1877, Louis Pasteur showed that the bacterial disease anthrax, which can cause respiratory failure, could be rendered harmless in animals with the injection of soil bacteria. In 1887, Rudolf Emmerich showed that cholera was prevented in animals that had been previously infected with the streptococcus bacterium and then injected with the cholera bacillus.

In the early 1920s, the British scientist Alexander Fleming reported that a product in human tears could brealdown (lyse) bacterial cells. Soon he made another discovery that changed the course of medicine. In 1928, Fleming discovered another antibacterial agent. He named this substance penicillin after the Penicillium mold that had produced it. By extracting the substance from plates, Fleming was able to show its effects; penicillin destroyed a common bacterium, Staphylococcus aureus, associated with sometimes deadly skin infections.

PetroleumPetroleum is one of the most important sources of energy today. But for petrol and diesel, fuels extracted from petroleum travel would be a nightmare. Petroleum is often food deep under the Earth surface. The first oil wells to extract petroleum were drilled in China in the 4th century or earlier. They were up to 800 feet deep and were drilled using bits attached to bamboo poles. The oil was burned to evaporate seawater and produce salt. By the 10th century, extensive bamboo pipelines connected oil wells with salt springs. Ancient Persian tablets indicate the medicinal and lighting uses of petroleum in the upper echelons of their society.

In the 8th century, the streets of the newly constructed Baghdad were paved with tar, derived from easily-accessible petroleum from natural fields in the region. In the 9th century, oil fields were exploited in Baku, Azerbaijan, to produce naphtha. The geographer Masudi in the 10th century, and by Marco Polo in the 13th century, described these fields whose output was hundreds of shiploads.

The modern history of oil began in 1853, with the discovery of the process of oil distillation. Crude oil was distilled into kerosene by Ignacy Lukasiewicz, a Polish scientist. The first "rock oil" mine was created in Bobrka, near Krosno in southern Poland in the following year and the first refinery (actually a distillery) was built in Ulaszowice, also by Lukasiewicz. These discoveries rapidly spread around the world, and Meerzoeff built the first Russian refinery in the mature oil fields at Baku in 1861.The first modern oil well was drilled in 1848 by a Russian engineer F.N. Semyenov, on the Aspheron Peninsula north-east of Baku.

By 1910, significant oil fields had been discovered in Canada (specifically, in the province of Alberta), the Dutch East Indies (1885, in Sumatra), Persia (1901, in Masjed Soleiman), Peru, Venezuela, and Mexico, and were being developed at an industrial level. The Indian petroleum industry dates back to 1890 when oil was first struck at Digboi in northeastern India. However, the most significant discovery of petroleum in India was that at Bombay High, on 19th February 1974, which, in reality, was the turning point in history of oil exploration in India.

OxygenOxygen supports all life on Earth and is essential for combustion and respiration, yet its very existence was not known until the 1770's, when scientists began to concern themselves with air and how it affects combustion. The ancient Greeks considered air to be an element composed of a single substance, and this view persisted through the centuries. The discovery of oxygen, its significance, and the capability for measuring it accurately required some major scientific breakthroughs.

In 1770, G.E. Stahl, a German physician, proposed a theory that received widespread acceptance. He claimed that all inflammable objects contained a material substance that he called "phlogiston," from a Greek word meaning "to set on fire." When an object burned, it poured its content of phlogiston into the air, and when all its phlogiston was gone, it stopped burning. Wood lost its phlogiston very rapidly, so that its passage into air was visible as flames. Stahl suggested that the rusting of metals also depended on the loss of phlogiston to surrounding air, except that metals lost their phlogiston so slowly that rusting was a gradual process.

Experiments to learn more about the principles of combustion were made in 1772 by a Scottish chemist, Joseph Black, and his student, Daniel Rutherford. They tried burning candles in closed containers of air and found that the candles eventually went out even though the containers still held a large amount of air. Mice put into these containers promptly died. Holding to the phlogiston theory, Rutherford came to the conclusion that the burning candles emitted phlogiston but a given volume of air could hold only a certain amount of phlogiston. When the saturation point was reached in the closed container, the air would not accept

any more phlogiston and the candle would go out because it could not continue to emit phlogiston. Rutherford believed that, in like manner, a living creature gives up phlogiston while breathing and when placed in air that is already saturated with phlogiston, can no longer breathe and must die.

The demolition of the phlogiston theory began with experiments carried on in 1774 by Joseph Priestly, an English clergyman who was interested in science. His experiments involved the heating of mercury by exposing it to sunlight concentrated through a magnifying glass. The heated mercury became coated with a reddish powder, which Priestly reheated at a higher temperature. The powder evaporated and turned into two gases, one of which was mercury vapor. The mercury vapor condensed into drops of mercury in the test vessel as it cooled. The other gas was invisible, but Priestly knew it existed because when he placed a smoldering splint of wood into it, the wood burst into flame, and mice put into this invisible gas became hyperactive. Priestly stuck to the phlogiston theory to explain these results. He thought that heated mercury lost some of its phlogiston and turned into mercury rust. When this rust was heated, it absorbed phlogiston from air and turned back into mercury. The invisible gas had also lost its phlogiston, and it drew phlogiston rapidly from the smoldering wood splint, causing the splint to burst into flame.

Priestly later traveled to Paris, where he discussed his experiments with a brilliant French chemist, Antoine Lavoisier, who had been carrying on his own experiments in combustion. Lavoisier's experiments had convinced him that phlogiston did not exist and combustion was caused by the combination of fuel with air. However, he was unable to prove his theory until Priestly described his experiments with heated mercury. Lavoisier had

burned candles in closed containers and he had observed that only one-fifth of the air was consumed during burning and the remaining four-fifths would not support combustion. After his discussions with Priestly, Lavoisier realized that what Priestly called two different kinds of air - one with phlogiston and one without - was really only one kind of air that contained two substances. Lavoisier called the one-fifth of the air that supported combustion "oxygen" (from the Greek words meaning "acid-producing," because he thought (wrongly) that oxygen was a necessary component of all acids). The four-fifths of the air that does not support respiration or combustion he called "azote" (from the Greek words meaning "no life"). Azote today is known as "nitrogen”.

PaperNobody knew paper 1900 years ago! A Chinese, T'sai Lun, invented paper in 105 AD. He experimented with a wide variety of materials and refined the process of macerating the plants fibers until each filament was completely separate. The individual fibers were mixed with water in a large vat and then a screen was submerged in the vat and lifted up through the water, catching the fibers on its surface. When dried, this thin layer of intertwined fiber became paper. T'sai Lun's thin, yet flexible and strong paper with its fine, smooth surface was known as T'sai Ko-Shi , meaning: "Distinguished T'sai's Paper" and he became the patron "saint of papermaking". It took about a hundred years for the use of paper to spread across central Asia. Books followed soon after. To produce books required printing. The very first books were printed in China, by stamping of seals (something like rubber stamps used nowadays) on paper.

The utility of books prompted people to improve the technique of making paper. The pioneers of this venture were mostly the Asians. Japanese discovered a method to make paper from waste paper. Egyptians used cloth rags to make paper. This knowledge gradually made its way to the western countries through the Muslim world - to Baghdad, Damascus and Cairo and ultimately to Europe in the 12th century.

The Europeans quickly grasped the merits of printing on paper. They improvised methods for making paper on a large scale. The earliest paper in Europe was made from recycled cotton and linen. This was an impetus for the trade of old rags. When this source became insufficient curious attempts were made to source new materials - the most macabre of which was the recycling of Egyptian mummies to create wrapping paper! They also experimented with fibers such as straw, cabbage,

wasp-nests and finally wood. Ultimately this quest ended when inexpensive and replaceable materials for papermaking-the long soft fibers of softwoods such as spruce, were discovered. A paper mill, that is an industry to produce paper on a large scale, was established for the first time in England in the year 1495.

RefrigeratorRefrigeration is the process by which heat from an enclosed space, or from a substance is removed and transferred to lower its temperature. A refrigerator uses the phenomenon of evaporation of a liquid to absorb heat. The liquid, or refrigerant, used in a refrigerator evaporates at an extremely low temperature, creating freezing temperatures inside the refrigerator.

Before the invention of refrigerator, people cooled their food with ice and snow, either found locally or brought down from the mountains. The first cellars were holes dug into the ground and lined with wood or straw and packed with snow and ice: this was the only means of refrigeration for most of history.

Refrigeration involves the following process: - a liquid is rapidly vaporized (through compression) - the quickly expanding vapor requires kinetic energy and draws the energy needed from the immediate area - which loses energy and becomes cooler. Cooling caused by the rapid expansion of gases is the primary means of refrigeration today.

William Cullen at the University of Glasgow was perhaps the first inventor who demonstrated a refrigerator in 1748. However, he did not use his discovery for any practical purpose. In 1805, an American inventor, Oliver Evans, designed the first refrigeration machine. Jacob Perkins built the first practical refrigerating machine in 1834; it used ether in a vapor compression cycle. An American physician, John Gorrie, built a refrigerator based on Oliver Evans' design in 1844 to make ice to cool the air for his yellow fever patients. German engineer Carl von Linden, patented not a refrigerator but the process of liquifying gas in 1876 that is part of basic refrigeration technology.

Till about 1929 refrigerators used the toxic gases ammonia (NH3), methyl chloride (CH3Cl), and sulfur dioxide (SO2) as refrigerants. Several fatal accidents occurred in the 1920s when methyl chloride leaked out of refrigerators. Three American corporations launched collaborative research to develop a less dangerous method of refrigeration; their efforts lead to the discovery of Freon. In just a few years, compressor refrigerators using Freon became the standard for almost all home kitchens. Only decades later, would people realize that these chlorofluorocarbons endangered the ozone layer of the entire planet.

The Cell phoneThe basic concept of cellular phones began in 1947, when some engineers in USA looked at crude mobile (car) wireless phones that were used in USA at that time. The number of the users of such phones was very small because the number of frequencies available for them was limited. It was realized that if transmission of radio waves was limited to a small area, small cells a frequency can be reused in another remote cell, thus increasing the traffic capacity of mobile phones substantially. However at that time, the technology to do so was nonexistent.

In USA, anything to do with wireless communication is decided by a department known as Federal Communications Commission (FCC). Since a cell phone is a type of two-way radio, in 1947, an American company AT&T proposed that the FCC allocate a larger number of frequencies of electromagnetic waves capable of radio communication to make mobile telephone service feasible. But FCC declined this request.

This position was reconsidered in 1968. AT&T and 'Bell Labs' then proposed the present form of cellular system. In this system many small, low-powered, broadcast towers, each covering a 'cell' a few kilometers in radius collectively cover a large area. Each tower uses only a few of the total frequencies allocated to the system. As the phones travel across the area, calls are passed from tower to tower.

Dr Martin Cooper, a general manager at an American company 'Motorola', is considered the inventor of the portable cellphone handset. Cooper made the first call on a portable cell phone in April 1973. He made the call to his rival, Joel Engel. Motorola was the first company to incorporate

technology into portable device that was designed for use even outside of an automobile. By 1977, AT&T and Bell Labs had constructed a prototype cellular system.

Pencil and PenThe Greeks introduced the earliest instrument of writing that approached the pen. They employed a writing stylus, made of metal, bone or ivory, to place marks upon wax-coated tablets. The tablets made in hinged pairs, closed to protect the scribe’s notes. Thus the first examples of handwriting (purely text messages made by hand) originated in Greece. A scholar from Greece, Cadmus invented the written letter - text messages on paper sent from one individual to another.

The instrument used for writing that dominated for the longest period in history (over one-thousand years) was the quill pen. Introduced around 700 A.D., the quill was a pen made from a bird feather. The strongest quills were those taken from living birds in the spring from the five outer left wing feathers. The left wing was favored because the feathers curved outward and away when used by a right-handed writer. Goose feathers were most common; swan feathers were of a premium grade being scarcer and more expensive. For making fine lines, crow feathers were the best, followed by the feathers of the eagle, owl, hawk and turkey.

Pencil was most likely invented in England, after some shepherds in Borrowdale found small pieces of a charred oak tree that had fallen during a storm, useful for marking sheep, sometime in 1564. Soon thereafter small pieces of this material were encased in wood to produce a sturdy and clean writing instrument that needed no ink. Many people have wondered why the core of a pencil is called “lead”. The answer perhaps lies in the fact that Greeks and Romans used small disc shaped pieces

of lead to write, way back in 20 B.C. That’s why material discovered by shepherds was initially known as “plumbago” (imitation Lead), until a Swedish scientist, W. Scheele, found it to be a form of carbon and gave it the name “graphite” (from the Greek word “Graphis” for writing). Fountain pens and the ballpoint pens came much later, the earliest surviving fountain pens date to the early 18th (or possibly later 17th) century; they are made of metal, or cut quills used as nibs. From the beginning of the 19th century, the number of fountain pen designs patented and produced began to multiply. Three major advances paved the way for the fountain pen’s widespread acceptance: the invention of hard rubber (a naturally-derived plastic, resistant to chemicals, easily machined, and relatively cheap); the availability of iridium-tipped gold nibs; and improved inks, not laden with clogging sediment. But, all these three factors fell into place later, sometime around 1870 - 1880.

ComputerThe story of invention of computer differs from the story of invention of television. It was invented not by any individual, rather through large commercial establishments. Several groups of people working for a large business houses made it possible. The earliest computer was somewhat like a programmable calculator; it could only make mathematical calculations. A German inventor, Konrad Zuse, is often credited with the invention of the first electronic computer is. He made the world's first electronic, fully programmable digital computer in 1941, with recycled materials donated by his colleagues in university. Five years later in 1946, John Mauchly and J Presper Eckert developed the ENIAC I (Electrical Numerical Integrator And Calculator) under a project sponsored by the U.S. military. This computer covered 167 square meters of floor space, weighed 30 tons, and consumed 160

kilowatts of electrical power. In one second, it could perform 5,000 additions, 357 multiplications or 38 divisions.

Later computers became significantly smaller. This became possible due to the invention of a device, the transistor. Three American scientists, John Bardeen, William Shockley, and Walter Brattain, invented transistor while working for the Bell Telephone Laboratories in U.S.A. (A business house established by Graham Bell -- the inventor of Telephone). They invented it accidentally while studying the behavior of crystals of germanium to find something to replace vacuum tubes as mechanical relays in telecommunications. The vacuum tubes, used at that time in various devices for communication, consumed lots of electricity and produced unnecessary heat. A transistor is made from semi-conductor materials. A semiconductor material is a kind if material that can conduct electricity as well as stop its flow (insulator). Chemical elements germanium and silicon are two examples of semiconductor materials. A transistor is the first device discovered to be capable of acting as a transmitter, converting sound waves into waves of electric current, and a resistor, controlling electric current. No doubt transistors soon replaced vacuum tubes in the computers. Computers made up of transistors were more reliable and consumed much less electricity.

The next step was the integration of many electric devices into a tiny small crystal of silicon, an integrated circuit (IC). Till 1959, it was believed that to make a computer more efficient it is necessary to increase the number of electrical components in it. After the invention of integrated circuits, hundred of transistors, resistors, capacitors and connecting wires, could be put into a single component -the chip. A chip is made on a single crystal of a semiconductor material. The technology for making

an IC was invented by two American engineers Jack Kilby, working for a company named Texas Instruments and Robert Noyce, the co-founder of the Fairchild Semiconductor Corporation. Further development of computer was due to the development of an IC specifically designed for computers. In 1971, a company ‘Intel’ introduced a microprocessor as an IC, the Intel 4004. Three employees of Intel are said to be responsible for the invention of this chip: Federico Faggin, Ted Hoff, and Stan Mazor. In this IC all the parts that made a computer think (i.e. central processing unit, memory, input and output controls) are on a single chip.

The person who can perhaps be called the inventor of personal computers is Douglas Engelbart. He invented or contributed to several interactive devices and features: the computer mouse, windows, computer video teleconferencing, email, the Internet and more. However, the real revolution in PC was the handiwork of a few computer whizkids: Bill Gates and Steve Jobs who developed software that is really user friendly.

Electric lampThe story of the invention of electric lamp goes back to 1811, when Sir Humphrey Davy discovered that an electrical arc passed between two poles produced light. In 1841, experimental arc lights were installed as public lighting along the Place de la Concorde in Paris. Other experiments were undertaken in Europe and America, but the arc light eventually proved impractical because it burned out too quickly. Inventors continued to grapple with the problem of developing a reliable electric light that would be practical for both home and public use as a viable alternative to light from burning gas.

However, the practical solution for producing light from electricity lay not in an electrical arc in open space, rather in electricity passed through a filament. The breakthrough theory became known, as the Joule effect after James Prescott Joule, who theorized that electrical current, if passed through a resistant conductor, would glow white-hot with heat energy turned to luminous energy. The problem was devising the right conductor, or filament, and inserting it in a container, or bulb, without oxygen because the presence of oxygen would cause the filament to burn out.

Sir Joseph Wilson Swan an English inventor was the first person to construct an electric light bulb, but he had trouble maintaining a vacuum in his bulb. Thomas Alva Edison the legendary American inventor solved this problem, and on October 21, 1879, he illuminated a carbon filament light bulb that glowed continuously for 40 hours.

In the period from 1878 to 1880 Edison and his associates worked on at least three thousand different theories to develop an efficient incandescent lamp. Incandescent lamps make light by using electricity to heat a thin strip of material

(called a filament) until it gets hot enough to glow. Many inventors had tried to perfect incandescent lamps to "sub-divide" electric light or make it smaller and weaker than it was in the existing arc lamps, which were too bright to be used for small spaces such as the rooms of a house.

Edison’s lamp was made up of a filament inside in a glass bulb from which all air had been removed. Edison was targeting a high resistance system that would require far less electrical power than was used for the arc lamps. He knew such small electric lights would be suitable for home use.

By January 1879, at his laboratory in Menlo Park, New Jersey, Edison had built his first high resistance, incandescent electric light. It worked by passing electricity through a thin platinum filament in the glass vacuum bulb, which delayed the filament from melting. Still, the lamp only burned for a few short hours. In order to improve the bulb, Edison needed all the persistence he had learned years before in his basement laboratory. He tested thousands and thousands of other materials to use for the filament. He even thought about using tungsten, which is the metal used for light bulb filaments now, but he couldn’t work with it given the tools available at that time.

AutomobilesTransportation had changed very little between the time of the Romans and the early 1800s. People walked, rode horses, or rode in slow vehicles pulled by horses. At sea, people relied upon wind and muscle power. The word Automobile means a self-propelled vehicle. Such vehicles do not need an animal to move rather they depend on the energy in a fuel, say coal, petrol, diesel etc.

Nicholas Cugnot, a French engineer in 1769, invented the first automobile. This automobile was based on a steam engine. It looked like a massive tricycle. This ancestor of automobiles can perhaps still be seen in Paris. In 1873, Amedee Bollee, another Frenchmen invented an automobile that was called Obe`issant, a French word meaning obedient. It looked like a bus.

However, steam engine proved impractical for a machine that was intended to challenge the speed of a horse-and-buggy. The invention of the practical automobile had to await the invention of a workable internal combustion engine. An internal combustion engine in contrast to a steam engine that burns its fuel outside the engine is any engine that uses the explosive combustion of a liquid fuel to push a piston within a cylinder - the piston's movement. The most common internal combustion engine type is gasoline powered. Others include those fueled by diesel, turns a crankshaft that then turns the car wheels via a chain or a drive shaft.

Gottlieb Daimler and Wilhelm Maybach built the first automobile based on internal combustion engine in Germany in 1889. Powered by a 1.5 hp, two-cylinder gasoline engine, it had a four-speed transmission and traveled at 10 mph. Another German, Karl Benz, also built a gasoline-powered car the same year. The gasoline-powered

automobile, or motor car, remained largely a curiosity for the rest of the nineteenth century, with only a handful being manufactured in Europe and the United States.

The first automobile to be produced in quantity was the 1901 Curved Dash Oldsmobile, which was built in the United States by Ransom E. Olds. Modern automobile mass production, and its use of the modern industrial assembly line, is credited to Henry Ford of Detroit, Michigan, who had built his first gasoline-powered car in 1896. Ford began producing his Model T in 1908, and by 1927, when it was discontinued; over 18 million had rolled off the assembly line.

Electric batteryA battery produces electricity using two different metals in a chemical solution. A chemical reaction between the metals and the chemicals frees more electrons in one metal than in the other. One end of the battery is attached to one of the metals; the other end is attached to the other metal. The end that frees more electrons develops a positive charge and the other end develops a negative charge. If a wire is attached from one end of the battery to the other, electrons flow through the wire to balance the electrical charge.

There is evidence that primitive batteries were used in Iraq and Egypt as early as 200 B.C. for electroplating and precious metal gilding. In 1748, Benjamin Franklin coined the term battery to describe an array of charged glass plates.

Around the 1790s, through numerous observations and experiments, Luigi Galvani, an Italian professor, caused muscular contraction in a frog by touching its nerves with electrostatically charged metal. Later, he was able to cause muscular contraction by touching the nerve with different metals without a source of electrostatic charge. He thought that animal tissue contained an innate vital force, which he termed "animal electricity."

In fact, it was Volta's famous disagreement with Galvani's theory of animal electricity that led Volta, in 1800, to build the voltaic pile to prove that electricity did not come from the animal tissue but was generated by the contact of different metals in a moist environment.

Most historians attribute the invention of the battery to Alessandro Volta since his voltaic pile was the first battery that produced a reliable, steady current of electricity.

Volta’s invention was to give rise to electrochemistry, electromagnetism and the modern applications of electricity. Also Galvani's idea of animal electricity were not useless either. Galvani’s research was soon to develop into electrophysiology and modern biology.

LoudspeakerFrom time immemorial people have been communicating through sounds because it is one of the most efficient and economical means of communication. However, sound produced by a person has its limitations. It can only travel a certain distance, in other words it is sometimes not loud enough to reach the target. This need was the mother of the invention of loudspeakers. A loudspeaker is a type of transducer, i.e. it is a device that can transform energy in one type of wave, motion, signal, excitation or oscillation into another. Loudspeakers convert electrical energy into mechanical energy, which in turn is converted into sound energy. Obviously a loudspeaker could not have been invented before electricity was discovered and means for producing it invented.

A loudspeaker is a type of transducer, i.e. it is a device that can transform energy in one type of wave, motion, signal, excitation or oscillation into another. Loudspeakers convert electrical energy into mechanical energy, which in turn is converted into sound energy.

Alexander Bell patented the first loudspeaker as part of his telephone in 1876. Ernst Siemens, a German in 1878, soon invented an improved version. The modern design of moving-coil loudspeaker was established by Oliver Lodge, a physicist and writer, involved the development of the wireless telegraph in 1898. He was also the first person to transmit a radio signal (in 1894, one year before Marconi did so), and received international recognition for his work. Since large powerful permanent magnets of the correct shape for loudspeaker construction were not freely available at reasonable cost at that time, these loudspeakers, found in early radio systems, utilized electromagnets.

The quality of sound produced from loudspeaker systems until the 1950s was rather poor. Developments in cabinet technology (e.g. acoustic suspension) and changes in materials used in the actual loudspeaker, such as the move away from simple paper cones, led to audible improvements. Paper cones (or doped paper cones, where the paper is treated with a substance to improve its performance) are still in use today, and can provide good performance. Polypropylene and aluminium are also used as diaphram materials.

MicrophoneA microphone is a device that converts sound waves into electricity. Microphones were first used with early telephones and then radio transmitters. In 1827, an English scientist ,Sir Charles Wheatstone, coin ed the phrase "microphone."

In 1876, Emile Berliner invented the first microphone used as a telephone voice transmitter. He had seen a Bell Company telephone demonstration at the U.S. Centennial Exposition and was inspired to find ways to improve the newly invented telephone. The Bell Telephone Company was impressed with what the inventor came up with and bought Berliner's microphone patent for $50,000.

In 1878 David Edward Hughes, invented the carbon microphone, which was later developed during the 1920s. Hughes's microphone was the early model for the various carbon microphones now in use.

With the invention of the radio, new broadcasting microphones were created. The ribbon microphone was invented in 1942 for radio broadcasting.

In 1964, Bell Laboratories researchers James West and Gerhard Sessler received a patent for an electret microphone. The electret microphone offers greater reliability, higher precision, lower cost, and a smaller size. It revolutionized the microphone industry, with almost one billion manufactured each year.

During the 1970's, dynamic and condenser mics were developed, allowing for a lower sound level sensitivity and a clearer sound recording.

Microwave ovenThe microwave oven is the first new method of cooking since man invented fire. You may be surprised to know that no one ever set out to discover the microwave oven. It was an accidental discovery.

Way back in 1940, two scientists, Sir John Randall and Dr. H. A. Boot, invented a device called a magnetron to produce microwaves in their lab at England's Birmingham University. The magnetron is a radar (radio detecting and ranging) device that bounces microwaves off the enemy's war machines to detect their presence.

In 1946, an American engineer named Dr. Percy Spencer, a self-taught engineer was performing tests on a magnetron tube when he got strong cravings for the chocolate bar that was in his pocket. He reached into his pocket only to be surprised by a nice gooey mess. Doc Spencer was well aware of the fact that the magnetron produced heat, but he did not sense any. However, he suspected that the magnetron had melted the chocolate, not his body heat. He needed to test his theory that the magnetron was cooking his food. He sent out for a bag of popcorn and placed it in front of the magnetron tube. The popcorn popped all over the floor!! Next morning he tried cooking up some eggs, one of his fellow colleagues was very curious and happened to get a bit too close - the egg blew up in his face.

Raytheon set out to make the first microwave oven. Since the magnetrons were used to make radars, they gave it the name Radar Range. Soon he succeeded in building the oven, but it was very large. After all, the 1940's were not known for miniaturization of electronics.

Now, that we know the story of invention lets know how food is cooked in a microwave oven. Microwaves are a type of radio waves. They can pass through the outer layer of food (just as they pass through the walls of a house) and heat the interior directly. They do this by setting molecules of water, fats, sugars, and other food components into rapid motion. Since a molecule in the middle of a piece of food can receive this energy as readily as one on the exterior, microwaves are sometimes said to cook food from the inside out. In practice, however, they are generally absorbed in the outer inch or so of a piece of food, which is why thick items that are cooked in a microwave oven can still be raw inside.

MagnetsThe most popular legend about the discovery of magnets is that of an elderly Cretan shepherd named Magnes. Legend has it that Magnes was herding his sheep in an area of Northern Greece called Magnesia, about 4,000 years ago. Suddenly both, the nails in his shoes and the metal tip of his staff became firmly stuck to the large, black rock on which he was standing. To find the source of attraction he dug up the Earth to find lodestones (load = lead or attract). Lodestones contain magnetite, a natural magnetic material. This type of rock was subsequently named magnetite, after either Magnesia or Magnes himself. People soon realized that magnetite not only attracted objects made of iron, but when made into the shape of a needle and floated on water, magnetite always pointed in a north-south direction creating a primitive compass. This led to an alternative name for magnetite, that of lodestone or "leading stone". For many years following the discovery of lodestone magnetism was just a curious natural phenomenon. The Chinese developed the mariner's compass some 4500 years ago. The earliest mariner's compass comprised a splinter of loadstone carefully floated on the surface tension of water.

Peter Peregrinus is credited with the first attempt to separate fact from superstition in 1269. Peregrinus wrote a letter describing everything that was known, at that time, about magnetite. However, significant progress was made only with the experiments of William Gilbert in 1600 in the understanding of magnetism. It was Gilbert who first realized that the Earth was a giant magnet and that magnets could be made by beating wrought iron. He also discovered that heating resulted in the loss of induced magnetism.

In 1820 Hans Christian Oersted, a scientist from Danemark, demonstrated that magnetism was related to electricity by bringing a wire carrying an electric current close to a magnetic compass which caused a deflection of the compass needle. This lead to the knowledge that whenever current flows there is be an associated magnetic field in the surrounding space, or more generally that the movement of any charged particle will produce a magnetic field.

Electric motorA broad definition of "motor" would be: any device that converts electrical energy into motion. As is so often the case with inventions, the credit for development of the electric motor belongs to more than one individual. It was through a process of development and discovery beginning with Hans Oersted's discovery of electromagnetism in 1820 and involving additional work by William Sturgeon, Joseph Henry, Andre Marie Ampere, Michael Faraday, and a few others.

The story of invention of electric motor dates back to 1831, when an American physicist Joseph Henry published an article in a science journal, describing a device that was basically the reverse of the electric generator. Instead of converting mechanical movement into an electric current, like the generator, his device used electric current to produce mechanical movement. Henry's motor was the first to be constructed, although inefficiency limited its potential. In 1834 American blacksmith Thomas Davenport improved the motor's operating principles, using four magnets, two fixed and two revolving. Davenport used his motor to operate his own drills and wood-turning lathes. He went on to incorporate his motor in the electric railway, electric trolley, electric piano, and electric printing press.

Meanwhile the English inventor scientist, Michael Faraday, had been making advances of his own. Faraday, having learned of Hans Christian Oersted's discovery that an electric current created a magnetic field, which could deflect a compass needle, set out to reverse the results and create an electric current from a magnetic field.

The motor built by Faraday consisted of a free-hanging wire dipping into a pool of mercury. A

permanent magnet was placed in the middle of the pool. When a current was passed through the wire, the wire rotated around the magnet. This motor is often demonstrated in school physics classes, but brine is sometimes used in place of the toxic mercury. This is the simplest form of a class of electric motors called homopolar motors.

The modern DC motor was invented by accident in 1873, when Zénobe Gramme, a Belgian electrical engineer, connected a spinning dynamo to a second similar unit, driving it as a motor.

AirplaneMen have dreamed of being able to fly for centuries. Leonardo da Vinci (1452-1519) imagined devices that would enable human beings to fly and drew pictures of such machines. In 1782 the Montgolfier brothers invented a hot air balloon that floated over Paris for 25 minutes. The development of powered balloons, however, did not lead to practical aircraft.

Around the turn of the twentieth century, dozens of people were working to invent the airplane. The period of active experimentation begins in 1891, when noted German engineer Otto Lilienthal began experimenting with hang gliders. Lilienthal took seriously the ideas advocated by Sir George Cayley almost a hundred years earlier. Through an extensive study of birds and bird flight, Cayley realized that the lift function and the thrust function of bird wings were separate and distinct, and could be imitated. Following in Lilienthal's footsteps, efforts to invent an airplane became commonplace in Europe. Although an occasional aircraft flew farther than 100 meters (about the length of a football field), this level of performance was exceptional. It was at such a juncture that the legendary Wright brothers entered the arena.

The American brothers Wilbur and Orville Wright, inspired by Lilienthal, decided in 1899 to master gliding before attempting powered flight. First, for a few months, the Wright brothers built and flew several kites, testing and perfecting their new ideas about a flight control system. In 1900, they used this system on a man-carrying glider for the first time. Before they risked their own necks, they flew the glider as a kite, controlling it from the ground. They flew three biplane (has two wings, one above the other) gliders and by 1902 they had developed a fully practical biplane glider. Their great innovation was that their glider could have been

balanced and controlled in every direction, by combining the actions of warping (twisting) the wings and turning the rudder for lateral control, and by using a device called an elevator for up and down movements without any need for the pilot to swing his torso and legs in order to control the flight direction. All flight control today has developed from this 1902 Wright glider.

The development of the airplane is a twentieth-century phenomenon. From the first powered aircraft to the creation of the supersonic transport, airplanes improved quickly. This was aided by the innovations of World War I and World War II. Demand for air travel led to the creation of an industry including aircraft construction companies, engine and equipment makers, as well as firms that built and operated airports.

AtomThe first person to propose that matter was made of atoms, and then write it down, was a Greek philosopher named Democritus. The Greek concept of the atom was unlike ours: to their minds a pickle was composed of small green sour atoms, a fire of hot light bright atoms, etc.A number of scientists, starting probably with Newton in the late 1600s, proposed a corpuscular, or atomic, model. But it wasn't until the late 1700s/early 1800s that a British scientist, John Dalton, proposed that all matter was made of atoms and actually used it to explain a bunch of experiments that had been done on gases, and to calculate atomic weights of elements. In addition to Dalton's work suggesting the atom because of fixed chemical combining rules, there was the astoundingly successful kinetic theory of gases, a subject of intense interest in the nineteenth century, which relies utterly on gases being made of little bits of flying matter.However, Dalton did not prove that atoms existed...he just showed that the concept of atoms was useful and helped explain a lot of data. Probably the best direct probe of the atom was first done by Rutherford and his student, C.T.R. Wilson, who invented the cloud chamber and used it to show that when thin gold foil is bombarded by helium nuclei (alpha particles), the particles are occasionally deflected by a very large angle, but usually pass straight through. This gave rise to the realization that the gold was composed of atoms, with a tiny nucleus at the middle, which could occasionally collide with an alpha particle and send it flying.

LaserA laser is a device that creates and amplifies a narrow, intense beam of coherent light.

The word laser is an acronym for light amplification by stimulated emission of radiation, although common usage today is to use the word as a noun -- laser -- rather than as an acronym -- LASER.

Light is a kind of radiation emitted by atoms. Atoms radiate light in random directions at random times. The result is incoherent light -- a technical term for what you would consider a jumble of photons going in all directions.

The trick in generating coherent light -- of a single or just a few frequencies going in one precise direction -- is to find the right atoms with the right internal storage mechanisms and create an environment in which they can all cooperate -- to give up their light at the right time and all in the same direction.

The principle of the laser was first known in 1917, when the most eminent scientist Albert Einstein described the theory of stimulated emission. However, it was not until the late 1940s that engineers began to utilize this principle for practical purposes. At the onset of the 1950's several different engineers were working towards the harnessing of energy using the principal of stimulated emission. Notable amongst them were: Charles Townes at the University of Columbia; Joseph Weber at the University of Maryland and Alexander Prokhorov and Nikolai G Basov at the Lebedev Laboratories in Moscow. These engineers were working towards the creation of what was termed a MASER (Microwave Amplification by the Stimulated Emission of Radiation), a device that amplified microwaves as opposed to light and soon

found use in microwave communication systems. Townes and the other engineers believed it to be possible create an optical maser, a device for creating powerful beams of light using higher frequency energy to stimulate what was to become termed the lasing medium.

However Theodore Maiman was the first scientist who made the first Laser in 1960 using a ruby crystal. But still Both Townes and Prokhorov were awarded the Nobel Science Prize in 1964.

The Laser was a remarkable technical breakthrough, but in its early years it was something of a technology without a purpose. It was not powerful enough for use in the beam weapons envisioned by the military, and its usefulness for transmitting information through the atmosphere was severely hampered by its inability to penetrate clouds and rain. Almost immediately, though, some began to find uses for it. Maiman and his colleagues developed some of the first Laser weapons sighting systems and other engineers developed powerful lasers for use in surgery and other areas where a moderately powerful, pinpoint source of heat was needed. Today, for example, Lasers are used in corrective eye surgery, providing a precise source of heat for cutting tissue.

VaccinationVaccination is a term coined by Edward Jenner, an English country doctor, for the process of administering live, albeit weakened, microbes to patients, with the intent of conferring immunity against a targeted form of a related disease agent. In common speech, 'vaccination' and 'immunization' generally mean the same thing.

Edward Jenner had studied nature and his natural surroundings since childhood. He had always been fascinated by the rural old wives tale that milkmaids could not get smallpox. He believed that there was a connection between the fact that milkmaids only got a weak version of smallpox, the non-life threatening cowpox, but did not get smallpox itself. A milkmaid who caught cowpox got blisters on her hands and Jenner concluded that it must be the pus in the blisters that somehow protected the milkmaids.

In 1796, Jenner decided to try out a theory he had developed. A young boy called James Phipps would be his guinea pig. He took some pus from cowpox blisters found on the hand of a milkmaid called Sarah. She had milked a cow called Blossom and had developed the tell-tale blisters. Jenner ‘injected’ some of the pus into James. This process he repeated over a number of days gradually increasing the amount of pus he put into the boy. He then deliberately injected Phipps with smallpox. James became ill but after a few days made a full recovery with no side effects. It seemed that Jenner had made a brilliant discovery.

Jenner encountered the prejudices and conservatism of the English society at that time. People could not accept that a country doctor had made such an important discovery and Jenner was publicly humiliated when he publisized his findings.

However, eventually his discovery had to be accepted – a discovery that was to change the world. So successful was Jenner's discovery, that in 1840 the government of the day banned any other treatment for smallpox other than Jenner's. Jenner did not patent his discovery as it would have made the vaccination more expensive and out of the reach of many. It was his gift to the world.

Clocks and watchesClocks, whether on the wall, or computers, or on our wrists in the form of watches, are the standard method for measuring time. The concept of time dates back to the ancient times. The prehistoric man began to come up with very primitive methods of measuring time by simple observation of the stars, changes in the seasons, day and night. This was necessary for planning nomadic activity, farming, sacred feasts, etc.

The earliest time measurement devices before clocks and watches were the sundial, hourglass and water clock.

The forerunners to the sundial were poles and sticks as well as larger objects such as pyramids and other tall structures. Later the more formal sundial was invented. It is generally a round disk marked with the hours like a clock. It has an upright structure that casts a shadow on the disk - this is how time is measured with the sundial.

The hourglass was also used in ancient times. It was made up of two-rounded glass bulbs connected by a narrow neck of glass between them. When the hourglass is turned upside down, a measured amount of sand particles stream through from the top to bottom bulb of glass. Today's egg timers are modern versions of the hourglass.

Another ancient device to measure time was the water clock or clepsydra. It was a container that was evenly marked and had a spout in which water dripped out. As the water dripped out of the container one could note by the water level against the markings what time it was.

One of the earliest clocks was invented by Pope Sylvester II in the 990s. Later on chimes or bells were added as well as dials to the clocks. Early clocks were powered by falling weights and springs. Clocks with pendulums came into existence later, in 1657.

Electric clocks came into being after 1850, but were not popular until the twentieth century. An electric motor with alternating current powers these clocks. Later digital clocks with LCD (liquid crystal displays) rivaled the electric clocks. Quartz clocks use the vibrations of a quartz crystal to power the clock.

Watches are different than clocks in that they are carried about or worn. The first watches appeared by the 1500s and were made by hand. They were very fancy and their faces were covered by fine metal strips to protect the markings. Watches were manufactured by machine in the mid 1800s.

At first watches had knobs on the outside that the wearer wound to keep the mainspring powered inside. Later on, self-winding watches derived power from the movement of the wearer. With the advent of quartz crystal watches with digital displays, the need for motors for watches has decreased.

WheelThe wheel is probably the most important mechanical invention of all time. Nearly every machine built since the beginning of the Industrial Revolution involves a single, basic principle embodied in one of mankind’s truly significant inventions. It’s hard to imagine any mechanized system without the wheel or the idea of a symmetrical component moving in a circular motion on an axis. From tiny watch gears to automobiles, jet engines and computer disk drives, the principle is the same.

The earliest known use of this essential invention was a potter’s wheel that was used at Ur in Mesopotamia (part of modern day Iraq} as early as 3500 BC. A Sumerian (ancient Iraq) pictograph, dated about 3500 BC, shows a sledge equipped with wheels. The idea of wheeled transportation may have come from the use of logs for rollers, but the oldest known wheels were wooden disks consisting of three carved planks clamped together by transverse struts.

The first use of the wheel for transportation was probably for Mesopotamian chariots in 3200 BC. A wheel with spokes first appeared on Egyptian chariots around 2000 BC, and wheels seem to have developed in Europe by 1400 BC without any influence from the Middle East. Because the idea of the wheel appears so simple, it’s easy to assume that the wheel would have simply "happened" in every culture when it reached a particular level of sophistication. However, this is not the case. The great Inca, Aztec and Maya civilizations reached an extremely high level of development, yet they never used the wheel. Even in Europe, the wheel evolved little until the beginning of the nineteenth century.

During the Industrial Revolution the wheel became the central component of technology, and was used in thousands of ways in countless different mechanisms.

Spoked wheels appeared about 2000 BC, when they were in use on chariots in Asia Minor. Later developments included iron hubs (centerpieces) turning on greased axles, and the introduction of a tire in the form of an iron ring that was expanded by heat and dropped over the rim and that on cooling shrank and drew the members tightly together.

Photocopy machinePhotocopying is a process, which makes paper copies of documents and other visual images quickly and cheaply. James Watt (the man who invented the steam engine) invented a letter-copying machine that can safely called the forerunner of the digital photocopier in the 1800's. though Chester Carlson is said to be the inventor of photocopying. He was a part time researcher and inventor. His job at his office required him to make a large number of copies of important papers. Carlson who was arthritic, found this a painful and tedious process. This prompted him to conduct experiments in the area of photoconductivity, through which multiple copies could be made with minimal effort. Carlson experimented with "electrophotography" in his kitchen and in 1938, applied for a patent for the process. He made the first "photocopy" using a zinc plate covered with sulfur. The word "10-22-38 Astoria" were written on a microscope slide, which was placed on top of more sulfur and under a bright light. After the slide was removed, a mirror image of the words remained. Carlson tried to sell his invention to some companies, but because the process was still underdeveloped he failed. At the time multiple copies were made using carbon paper or duplicating machines, and people did not feel any dire need for an electronic machine. Between 1939 and 1944, over 20 companies including IBM and GE, both of which did not believe that there was a significant market for copiers, turned down Carlson.

In 1944, the Battelle Memorial Institute, a non-profit organization in Columbus, Ohio, contracted with Carlson to refine his new process. Over the next five years, the institute conducted experiments to improve the process of electrophotography. In 1947 Haloid (a small New York based organisation

manufacturing and selling photographic paper at that time) approached Battelle to obtain a license to develop and market a copying machine based on this technology.

Haloid felt that the word "electrophotography" was too complicated and did not have good recall value. After consulting a professor of classical language at Ohio State University, Haloid and Carlson changed the name of the process to "Xerography", derived from Greek words which meant "dry writing". Haloid decided to call the new copier machines "Xerox" and in 1948, the word Xerox was trademarked.

In the early 1950s, RCA (Radio Corporation of America) introduced a variation on the process called Electrofax where images are formed directly on specially coated paper and rendered with a toner dispersed in a liquid.

AluminumThe common metal, Aluminum is not found naturally, but rather as an ore (alumina) typically found in most soils and in high concentrations in a clay-like substance called bauxite. It is one of the more abundant minerals (approximately 8% of the minerals in the earth’s crust) and is the earth’s most abundant metal. Bauxite is usually mined at or near the surface of the earth, using power shovels or draglines. The word bauxite (a name given to a number of aluminum oxides) comes from Les Baux, France where it was discovered in 1821. Bauxite is mined and typically exported from Guinea, Australia, and Brazil. Bauxite ranges in color from yellowish-white to dark, plum-like red, and may come in the forms of a fine powder or a clay.

Ever since ancient times, people have been using alum (one of the aluminum compounds found in nature). People used alum clays to make pottery, utensils, dyes, and medicines. The earliest known uses of alum date back to 5,300 BC.

It was not until the 1800’s that chemists were able to successfully separate aluminum metal from the other elements in the bauxite clay. In the 1800’s aluminum was popularly called "the metal from clay." When first commercially available, aluminum was near priceless in value (in fact, Emperor Napoleon III served his most honored guests with aluminum forks and spoons, instead of the usual gold or silver!). Making aluminum metal from bauxite requires enormous amounts of energy because an electrochemical ("loosening by electricity") process is necessary to remove the other elements that have bonded with the aluminum. Recycling aluminum requires approximately 95% less energy than producing the metal from bauxite, because the base metal is already identified and is then simply re-melted.

GlassGlass is an inorganic solid material that is usually clear or translucent with different colors. It is hard, brittle, and stands up to the effects of wind, rain or sun. Glass has been used for various kinds of bottles and utensils, mirrors, windows and more.

Archaeological findings indicate that glass was first made in the Middle East, sometime in the 3000's B.C. It appears to have been produced as far back as the second millennium BC by the Egyptians & perhaps the Phoenicians. In the beginning glass manufacturing was slow and costly. Glass melting furnaces were very small and hardly produced enough heat to melt glass properly. In ancient times, glass was a luxury item and few people could afford it.

An unknown person discovered the blowpipe in the 1st century B.C. on the Phoenician coast. Glass manufacturing flourished in the Roman empire and spread from Italy to all countries under Roman jurisdiction. Due to mass production, glass become an everyday object and was removed from the list of luxuries. The glassblowing innovation, along with the backing of the powerful Roman Empire, made glass products more accessible to the common people. As the size of the Roman Empire increased, the art of glass making spread to many other countries.

During the 15th century in Venice, the first clear glass called cristallo was invented and then heavily exported. In 1675, glassmaker George Ravenscroft invented lead crystal glass by adding lead oxide to Venetian glass. On March 25, 1902, Irving W Colburn patented the sheet glass drawing machine, making the mass production of glass for windows possible. A patent for a "glass-shaping machine" was granted to Michael Owen on August 2, 1904.

The immense production of bottles, jars, etc. owes its inception to this invention.

Portland CementCement is an ultra-fine gray powder that binds sand and rocks into a mass or matrix of concrete necessary to build houses, bridges and skyscrapers.

Ever since the civilizations first started to build, people have sought a material that would bind stones into a solid. The Assyrians and Babylonians used clay for this purpose, and the Egyptians advanced to the discovery of lime and gypsum mortar as a binding agent for building such structures as the Pyramids. The Greeks and the Romans further developed other kinds of cement that produced structures of remarkable durability.

The secret of Roman success in making cement can be traced to the mixing of slaked lime with pozzolana, a volcanic ash from Mount Vesuvius. This process produced cement capable of hardening under water. During the Middle Ages this art was lost and it was not until the scientific spirit of inquiry revived that we rediscovered the secret of hydraulic cement -- cement that will harden under water.

Repeated structural failure of the Eddystone Lighthouse off the coast of Cornwall, England, led John Smeaton, a British engineer, to conduct experiments with mortars in both fresh and salt water. In 1756, these tests led to the discovery that cement made from limestone containing a considerable proportion of clay would harden under water.

There were several other men who experimented in the field of cement during the period from 1756 to 1830, for example, L. J. Vicat and Lesage in France and Joseph Parker and James Frost in England. Before portland cement was discovered and for some years after its discovery, large quantities of natural cement were used. Natural cement was produced by burning a naturally occurring mixture

of lime and clay. Because the ingredients of natural cement were mixed by nature, its properties varied as widely as the natural resources from which it was made.

The invention of Portland cement is generally credited to Joseph Aspdin, an English mason. In 1824, he obtained a patent for his product, which he named Portland cement because it produced a concrete that was the colour of the excellent natural stone quarried on the Isle of Portland, a limestone peninsula in the English Channel west of the Isle of Wight. The name has endured and is used throughout the world, with many manufacturers adding their own trade or brand names.

BicycleBicycle is a two-wheeled device for human transportation. It requires balancing. Its invention has a long history, with the earliest confirmed example dating back to early 19th century.

There are many claims for the invention of bicycle-like machines but most of them are found to be unreliable. A French man Comte de Sivrac is said to have developed a two-wheeler, called a celerifere in 1791. The celerifere supposedly had two wheels set on a ridged wooden frame and no steering, directional control being limited to that attainable by leaning. A rider was said to have sat astride the machine and pushed it along using alternate feet. We now know that the celerifere never existed and that it was a mis-interpretation from the well known French cycle historian Louis Baudry de Saunier in 1891.

The first reliable claim for a practically used bicycle was by Karl von Drais. Drais invented his Laufmaschine (running machine) of 1817 that was called draisine by the press and later velocipede. In contrast to the non-existent celerifere, von Drais's machine was steerable. It is said that his interest in finding an alternative to the horse was the starvation and death caused by crop failure in 1816 ("eighteen hundred and froze to death," following the volcanic eruption of Tambora). On his first reported ride from Mannheim on June 12, 1817, he covered eight miles (13 km) in less than an hour. The wooden draisine weighed 48 pounds (22 kg), had brass bushings within the wheel bearings, a rear-wheel brake and 6 inches (152 mm) trail of the front-wheel for a self-centering castor effect. This design sparked a short lived fashion among wealthy dandies and several thousand copies were built and used, primarily in Western Europe and in North America. In Britain, where a D. Johnson introduced

the machine as the "pedestrian curricle," the Corinthians of the Regency adopted it, although the poet John Keats referred to it as "the nothing" of the day. Riders wore out their boots surprisingly rapidly, and the fashion ended within a couple of years.

Another early design is said to have come from Kirkpatrick MacMillan, a Scottish blacksmith 1839. He developed a rear wheel drive design using front mounted treadles and connecting rods to a rear crank. He is associated with a the first recorded instance of a cyclist committing a traffic offence, a newspaper reporting in 1842 an accident in which he knocked somebody down and was fined five British shillings in Glasgow. However, the documentary evidence between this treadle-drive machine and MacMillan is thought to be tenuous by some bicycle historians. Several machines of this type were made (one of which is available in the Science Museum (London)), however, this design did not have long lasting influence.

The design of bicycles and other self-propelling vehicles progressed gradually. Mechanics experimented with pedal- or handle-driven three- or four-wheeled designs, but these suffered greater weight and higher rolling resistance. However, Willard Sawyer in Dover successfully manufactured such vehicles and exported them worldwide in the 1850s.

IronPeople have utilized iron since time immemorial. Evidence for the use of iron can be found as early as 4,000 B.C.., but some historians believe it was in use prior to that time. Initially, iron was expensive and precious. The technology of how to press it was a closely guarded military secret.

Originally, iron was obtained from meteorite deposits, but as those supplies dwindled, the method of reduction of iron ore in furnaces was developed. By 1200 B.C.., iron smelting techniques had made iron a viable material for all weapons and tools. Because of the relatively low temperatures attainable from furnaces prior to the Middle Ages, repeated heating and hammering in a hot charcoal fire was necessary to work out the carbon and other impurities and forge the metal into desired shapes. Around 1300, use of the blast furnace began to spread throughout Europe. The furnace used a steady stream of air to increase the intensity of the heat. The air was produced by bellows or by water pressure. As a result, iron production was streamlined and new industries like blacksmithing, wire drawing, and needle making emerged.

Cast iron was known but not widely used for a long time. It was too brittle to be worked the same way as wrought iron. But in 1709, Abraham Darby started using coke instead of coal as a fuel to maintain the furnace heat. The result was a product that was much stronger than previous cast iron. Darby's method also made it possible to mass produce iron cheaply and in standard shapes. Eventually, his foundry at Coalbrookdale, England, produced cast iron cylinders for train engines. Englishman Henry Cort developed a grooved rolling mill in 1783 for the production of iron bars.

Soon thereafter Cort developed a puddling process for purifying iron from pig iron. In 1856 Sir Henry Bessemer invented a conversion process that blew air directly through the molten iron for the efficient production of steel from iron ore. This was significant for the iron industry, since steel replaced iron in importance within fifty years of Bessemer's invention. The demand for iron as a building material greatly increased as architects began to adopt the use of iron building frames, partly as a fire prevention measure. In 1848 American James Bogardus built a sugar mill in New York entirely of cast iron. One unique feature of the building was that the beams and joists were interchangeable. Similarly William Jenney, in 1885 in Chicago, designed the first iron load-bearing frame commercial building.

Throughout the seventeenth and eighteenth century iron was used extensively for the railways. It was used in building locomotives, bridges, and railway tracks. It played a major role in the rapid industrial development worldwide and in the expansion of the British Empire in India. Iron was also important for the shipping industry. Therefore new techniques were developed to increase the strength and durability of iron. The process of galvanizing developed in the 1700s was later applied to iron. In galvanization, a coating of zinc bonded to the iron gave it between fifteen and thirty years of protection against rust.

The production of iron is considered one of the greatest industrial developments in history and remains a guideline for evaluating technological advancement in developing countries like India.

ToothpasteToothpaste is one of those inventions, like the wheel and the calendar, that doesn't seem to have a definite inventor or birthdate.

Almost 5000 years ago, people in ancient Egypt were cleaning their teeth using a recipe of powdered ashes, myrrh, powdered egg shells and pumice. It is thought that they applied this paste to their teeth with their fingers.

Although toothpaste was used as long ago as 500 BC in both China and India; modern toothpastes were developed in the 1800s. In 1824, a dentist named Peabody was the first person to add soap to toothpaste. John Harris first added chalk as an ingredient to toothpaste in the 1850s. In 1873, Colgate mass-produced the first toothpaste in a jar. In 1892, Dr. Washington Sheffield of Connecticut manufactured toothpaste into a collapsible tube. Sheffield's toothpaste was called Dr. Sheffield's Creme Dentifrice. In 1896, Colgate Dental Cream was packaged in collapsible tubes imitating Sheffield. Advancements in synthetic detergents made after WW II allowed for the replacement of the soap used in toothpaste with emulsifying agents such as Sodium Lauryl Sulphate and Sodium Ricinoleate. A few years later, Colgate started to add fluoride to toothpaste.

ThermometerThermometer is an instrument for indicating temperature and measuring its changes. Galileo Galelei the famous Italian scientist made the first such device, which consisted of a glass bulb containing air, connected to a glass tube of small bore dipping into a colored liquid. Though it was very sensitive to variations of temperature, it was not satisfactory as a measuring instrument, because it was also affected by variations of atmospheric pressure.

The invention of the type of thermometer familiar at the present day, containing a liquid hermetically sealed in a glass bulb with a fine tube attached, is also generally attributed to Galileo at a slightly later date, about 1612. Alcohol ~77% was the liquid first employed, and In order to render the readings of such, instruments comparable with each other, it was necessary to select a fixed point or standard temperature as the zero or starting-point of the graduations. Instead of making each degree a given fraction of the volume of the bulb, which would be difficult in practice, and would give different values for different liquids, it was soon found to be preferable to take two fixed points and to divide the interval between them into the same number of degrees. It was natural in the first instance to take the temperature of the human body as one of the fixed points. In 1701 Sir Isaac Newton proposed a scale in which the freezing point of water was taken as zero, and the temperature of the human body as 1a. About the same date (1714) Gabriel Daniel Fahrenheit proposed to take as zero the lowest temperature obtainable with a freezing mixture of ice and salt, and to divide the interval between this temperature and that of the human body into 12. To obtain finer graduations the number was subsequently increased to 96. The freezing point of

water was at that time supposed to be somewhat variable, because as a matter of fact it is possible to cool water several degrees below its freezing-point in the absence of ice. Fahrenheit showed, however, that as soon as ice began to form the temperature always rose to the same point, and that a mixture of ice or snow with pure water always gave the same temperature. At a later period he also showed that the temperature of boiling water varied with the barometric pressure, but that it was always the same at the same pressure, and might therefore be used as the second fixed point (as Edmund Halley and others had suggested) provided that a definite pressure, such as the average atmospheric pressure, were specified.

Shortly after Fahrenheit’s death (1736) the freezing and boiling-points of water were generally recognized as the most convenient fixed points to adopt, but different systems of subdivision were employed. Fahrenheit~ scale, with its small degrees and its zero below the freezing point possesses undoubted advantages for meteorological work, and is still retained in most English-speaking countries. But for general scientific purposes, the centigrade system, in which the freezing point of water is marked 0 and the boiling-point 100, is now almost universally employed, on account of its greater simplicity from an arithmetical point of view.

With the advent of semiconductors, solid state thermometers were invented. Unlike a mercury or alcohol based thermometer, there is no liquid in such thermometers. They are based on the variation of electrical conductivity with temperature. One can read the temperature on a digital display of a modern digital thermometer.

SoapThe need for a substance to help remove dirt, grease, foodstuffs, pitches, bodily excretions, etc., has always been a part of the human experience. It has probably always played a role in human history. Before soap became an intentionally produced product, it was extracted from plants like yucca, soapwort, and horsetail.

The first known written mention of soap was on Sumerian clay tablets dating about 2500 B.C. The tablets spoke of the use of soap in washing wool. Another Sumerian tablet, describes soap made from water, alkali, and cassia oil. Historical evidence shows that Egyptians bathed regularly and that they combined animal and vegetable oils with alkaline salts to create a soaplike substance for washing.

Ancient Roman legend gives soap its name: From Mount Sapo, where animals were sacrificed, rain washed a mixture of melted animal fats and wood ashes down into the Tiber River below. There, the soapy mixture was discovered to be useful for washing clothing and skin. It is believed that the Romans acquired the knowledge of soap from the Gauls.

With the fall of the Roman Empire, the popularity of soap and bathing in Europe went into decline. Though many non-European cultures maintained bathing practices throughout the medieval period, it wasn't until several centuries later that bathing would come back into fashion in Europe. Soapmakers' guilds began to spring up in Europe during the seventh century. Secrets of the trade were closely guarded. The training and promotion of craftsmen within the trade was highly regulated. Southern European countries, such as Italy, Spain, and France were early production centers for soap

as they had an excellent supply of oil from olive trees and barilla ashes, which they used to make lye.

The English began manufacturing fancy varieties of soap during the twelfth century although soap was a heavily taxed luxury item, In Colonial America, soap was made by women producing it out of their homes seasonally. The commercial production of soap did not start until the early 1600's when enterprising soapmakers from England began arriving in USA.

Scientific advancements that affected the soapmaking trade began with Nicholas Leblanc, a French chemist who invented a process that allowed inexpensive production of soda ash. Michel Chevreul's in the early 1800s made significant discoveries about the relationship of fats, glycerine, and fatty acids and thus laid the groundwork for the chemistry of soaps and fats. During the mid-1800s, Belgian chemist Ernest Solvay discovered the ammonia process that improved the methods for extracting soda ash from common salt. This increased the availability and quality of soda ash for soapmaking.

As a result of these scientific achievements, soap became a popular and easy to-obtain commodity. It also began to take on many different identities: soap for bathing, soap for clothing, soap for cleaning.

CinemaCinema can be described as the projection of moving photographic pictures to an audience. The invention of cinema cannot be credited to any one person alone--various individuals played key roles in the development of machines that could project moving photographic pictures to an audience, but still Louis Le Prince and the Lumière brothers are credited with the invention of cinema. Le Prince built the single lens camera in 1888, and the Lumière developed Cinématographe in 1895 .

The evolution of this technique was dependent on a handful of technical principles. In 1832 Joseph Antoine Ferdinand Plateau (1801-83) constructed a device which created the illusion of movement through the successive presentation of still images showing phases of that movement. Photography, the permanent record of optically-formed images on light-sensitive material, was perfected simultaneously by Louis Daguerre (1787-1851) and William Henry Fox Talbot (1800-77) in 1839. Thus, the technical principles for cinematography were essentially understood by that date.

By the mid-1880s the key requirements for cinematography were: the need for long strips of pictures and a method of moving the strip intermittently at a fast enough rate to record movement smoothly--around sixteen pictures per second. In 1885, George Eastman (1854-1932) introduced a paper-based roll film. The Le Prince single lens camera made use of Eastman's paper roll film to record a sequence of images. It is claimed that in October 1888, it was used to take 20 consecutive pictures of Leeds Bridge at a rate of about 16 pictures per second. The camera and the frames still exist, although no definite proof of their date exists. But an English patent applied for by Le Prince (1842-1890?), a French showman engineer

and inventor, on January 1888 describes the principles of cinematography.

Thomas Alva Edison, the famous American inventor, introduced moving pictures to the general public when he opened in New York in 1894the first Kinetoscope parlour. The Kinetoscope was a coin-operated machine, which gave a 'show' lasting about twenty seconds for a single viewer--the original peepshow.The brothers Louis (1864-1948) and Auguste (1862-1954) Lumière were the most successful photographic plate manufacturers in France. They

first saw a Kinetoscope in the summer of 1894. Impressed by the demonstration but put off by the high prices demanded by Edison's agents, they decided to develop their own product. In February 1895, they patented a combined camera and projector,

which used an intermittent claw derived from the mechanism used in sewing machines to move the cloth.

Tape recorderA tape recorder records sound on a magnetic tape. Its basic principle was worked out theoretically in an 1888 by the English inventor Oberlin Smith (1840-1926). It was, however, 10 years later that Smith's ideas were adapted and the first working magnetic tape recorder was introduced.

In 1898, a Danish inventor and physicist Valdemar Poulsen invented a device that recorded and reproduced sounds by residual magnetization of a steel wire. The telegraphone, as it was called, was demonstrated at the 1900 World Fair in Paris, but the world took little notice of this new technology at the time. The invention of magnetic recording tape is variously attributed to J. A. O'Neill (b.1909), who is said to have created a paper version in 1927 in the United States, and the German engineer Fritz Pfleumer, who in 1928 developed a tape made by bonding a thin coating of oxide to strips of either paper or film. It was Pfleumer who filed the first audiotape patent in 1929. There is no doubt, however, that audiotape was an improvement over existing methods, such as records, for recording and storing sound. The tape was easier to use, store, and edit, and less expensive to produce. Later, a German electronics firm AEG produced a prototype of a record/playback machine, called a magnetophon, based on Pfleumer's idea, but using plastic tape in 1935. A German company BASF further improvised this technique.

The first public tape recording was made by the London Philharmonic Orchestra at BASF in 1936. Other recording devices were also being developed concurrently. In 1937 or 1938, Marvin Camras, a U.S. inventor, built a magnetic wire recorder, using a variation on the early work of Poulsen. His recorder used a revolutionary magnetic recording head to record around the wire symmetrically. Early

versions of his recorders were used during World War II for training and strategic purposes, such as to simulate battle sounds at noninvasion locations and therefore mislead the enemy. Camras went on to develop his recording techniques for home use. He invented the first magnetic coatings that modern recording tape is based on; these coatings are used in videotape, computer tape, and floppy disks for personal computers. He also discovered high-frequency bias, used on almost all tape recorders today to improve sound quality, and developed multi-track tape recording, magnetic sound for motion pictures, videotape recorders, a variety of improved recording heads, and stereophonic sound reproduction. Thin plastic tapes have become the medium universally used in tape recorders. The tapes have magnetic coatings consisting of magnetically active particles, most commonly iron oxide and chromium dioxide. Each of these particles, in effect, is a tiny permanent magnet embedded in the coating. As the tape passes around the five magnetic heads of the tape recorder, sound is recorded, replayed, or erased according to the heads that are activated. A recording head magnetizes the passing tape in such a way that the magnetic particles on it are realigned. The resulting magnetization pattern remains on the tape, which may be rewound and

replayed as often as desired, until erased or changed. The audiocassette, introduced in 1963 by the Philips Company of the Netherlands, was made possible by Pfleumer's earlier development of audiotape. Audiotape was used in a reel-to-reel format, which was complicated and unwieldy, since the user had to thread tape through the machine and onto a take-up reel. Until the audiocassette format, sound recording technology had remained primarily a professional tool. Because of the ease and economy of the audio-cassette, magnetic

recording tape recordings could compete with long playing (LP) records (LPs). The cassette was

immediately popular because it made inserting, advancing, and rewinding a tape fast and easy; it could also be stopped and ejected at any point in the tape.