Invention Stories

8/3/2019 Invention Stories

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Inventions and DiscoveriesElectromagnetic waves

.................................................................. 3The Wireless

.................................................................................. 5

Television........................................................

............................. 12Camera

......................................................................................... 15Electricity

.................................................................................... 17Blood groups

............................................................................... 19

Printing ....................................................................................... 21Bacteria

........................................................................................ 23Cells

............................................................................................. 28Antibiotics

................................................................................... 30Petroleum

..................................................................................... 32Oxygen

........................................................................................ 34Refrigerator

.................................................................................. 39Pencil and Pen

............................................................................. 43Computer

..................................................................................... 44Electric lamp

................................................................................ 47Automobiles

................................................................................ 50Electric battery

............................................................................. 52Loudspeaker

............................................................

.................... 54Microphone

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....................... 56Microwave oven

.......................................................................... 58Airplane

....................................................................................... 64

Laser......................................................

...................................... 67Vaccination

.................................................................................. 70Clocks and watches

..................................................................... 72Wheel

........................................................................................... 74

Glass ............................................................................................ 80Portland Cement

.......................................................................... 82Bicycle

......................................................................................... 84

.................................................................................................... 86Iron

.............................................................................................. 87Toothpaste

.................................................................................... 90Thermometer

............................................................................... 91Soap

............................................................................................. 94Cinema

......................................................................................... 96Tape recorder

............................................................................... 98 Electromagnetic wavesIn 1831, a British scientist Michael Faradaydiscovered that changing electric current in a coil ofwire can induce a current in a nearby coil. Thecurrent induced in the second coil is proportional toits number of turns. James Clerk Maxwell, acompatriot of Faraday, was a theoretician. Atheoretician is a scientist who does not work withinstruments or devices rather he dabbles with

mathematical formulations of observations. In 1865,as a result of his studies, he discovered themechanism of interaction between electricity and


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magnetism. He suggested that a change in electriccurrent can start a train of waves, theelectromagnetic waves, that radiate into space justlike light waves. According to him, the onlydifference between a light wave and anelectromagnetic wave is a characteristic of waves-the wavelength. Not all scientists accepted

Maxwell's ideas; after all there was no proof of theexistence of electromagnetic waves. The BerlinAcademy of Science offered a prize to anyone whocould prove that electromagnetic waves exist. In1879, Heinrich Rudolf Hertz, a German scientisttook the challenge in 1886.Hertz knew the work of Faraday. He devised asimple 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 thefirst wire coil. The second coil had many more turnsthan the first coil. As per the discovery of Faraday

the voltage developed in the second coil was muchhigher than that of the battery. This current was ledto a pair of capacitors. (A capacitor is a pair ofmetal plates that can accumlate electricity untilthey can hold no more.) As soon as the capacitorswere charged to their capacity they discharged bysending an electric spark between two small metallic balls. The second device had similar ballsconnected to a wire that was bent into circle and itwas placed at a distance from the first device. Hedemonstrated that whenever an electric spark wasgenerated in the first device a spark can beobserved in the second device also, even though

the two were not connected through any wires. Theonly way these two devices could communicatewith one another was through electromagneticwaves. This proved Maxwell's ideas. The WirelessAfter it was discovered that out of variouselectromagnetic waves, only those havingwavelength more than a meter could be used forremote wireless communication. For example, lightwaves could not be used for communicationbecause most common objects obstruct them. Theycannot pass through a wall of a building.Electromagnetic waves that can go across walls andhence can be used for long distance communicationare called radio waves. They can be transmittedwithout wires or through wires, just like electricity. Itwas also found that radio waves having nearlyequal wavelength interfere with one another, ifreceived simultaneously at a particular location.Therefore radio waves of a particular wavelengthcan be used to communicate to people at aparticular location only if nobody else istransmitting radio waves of the same wavelength.Many inventors in different countries triedsimultaneously to invent a communication deviceusing radio waves. For example, in 1893 a scientist

born in Hungary, Nikola T esla, made the first publicdemonstration of such a system. He described anddemonstrated in detail the principles of radio


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communication. The apparatus that he usedcontained almost all the elements that were usedlater. In 1894, an Indian scientist, Jagdish ChandraBasu, also demonstrated publicly the use ofelectromagnetic waves in Kolkata. He was notinterested in patenting his work, so his work is notrecognized internationally. In the same year a

British physicist, Sir Oliver Lodge, demonstrated thereception of Morse code signalling using radiowaves with the help of a detecting device -- acoherer. This coherer was a tube filled with ironfilings. It was invented by an Italian, T emistocleCalzecchi-Onesti, in 1884 to drain off electricity during lightening. Edouard Branly of France andAlexander Popov of Russia later produced improvedversions of the coherer. Many people claim thatPopov was the first person to develop a practicalcommunication system.The inventor who is generally recognized as the

inventor of wireless telegraph is Gugliemo Marconi,an Italian. He began by building an apparatussimilar to the one used by Hertz. He added atelegraph key to the spark generator, so that hecould send signals corresponding to the dots anddashes of the Morse code. T o check whether it wasa practical communication device Marconi movedhis appratus outdoors to try its transmission-reception over long distances. During theseexperiments he made a lucky discovery: When oneterminal of the generator and receiver wereconnected to the ground, communication waspossible across longer distances. He also discovered

the need for antenna (aerials); they transmit signalsfrom the transmitter to space and from space to thereceiver equipment. By 1895, Marconi haddeveloped a device with which he could sendsignals across a few kilometers. Marconi got apatent for his inventions in 1896, the worlds firstpatent for radio communication. After patentinghis invention Marconi established a company calledMarconis Wireless T elegraph Company in London. In1898 Marconi successfully transmitted signalsacross the English Channel. The most dramatic useof wireless was for rescuing ships in distress.Several ships were equipped with wirelesstelegraphy equipment, they could send or receivedistress messages from ships sailing nearby.Till the beginning of the twentieth century, wirelesscommunication was limited to telegraphy. Manypeople dreamt of wireless telephony at that time,but the technology to achieve that was notavailable.Sound waves are continuous waves, their frequencyis much lower than that of electromagnetic waves.(Frequency isanothercharaceristic of awave very closely

related to itswavelength). Forwireless


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communication asound signal has tobe converted into aradio wave. It wassoon found that anyelectric signal canbe carried on a radio

wave (modulation of electromagnetic waves). Allthat was necessary for wireless communication ofsound was an equipment that could generateelectric current having frequency of the radiowaves. Several inventors invented such devices.The most notable amongst them was Nikola T esla,who invented the alternating current and ErnstAlexanderson who built the first alternator thatcould produce alternating current having frequencyabout 50 thousand cycles.Although the exact time when the human voice wasfirst transmitted by radio is debateable, it is claimed

that speech was first transmitted across theAmerican continent, from New York City to SanFrancisco, in 1915. During the First World Warradiotelephony between ground and aircraft wasalso tried. The first ship-to-shore two way radioconversation occurred in 1922. However, a publicradiotelephone service for people at sea wasinaugurated in 1929. At that time telephone contactcould be made only with ships within 2000 km ofshore. T oday every large ship wherever it may be onthe globe can be contacted using wirelessequipment. The TelephoneThe success of telegraph by 1874 enthused several

young minds in Europe and America. People starteddreaming about the possibility of talking throughwires, but no body knew how voice could beconverted into electric current and vice versa. Onesuch young man was Alexander Graham Bell. Hisfather was a speech teacher who had worked out asystem called visible speech. This system usedsymbols to represent all of the sounds that peoplemake while speaking. He hoped to use this "soundalphabet" for teaching the art of speaking to deafpeople. Deaf people have trouble speaking clearlybecause they cannot hear what they are saying.Young Alexander Bell was fascinated by his father'swork. When he was sixteen years old his fatherchallenged him to build a machine that could makespeech sounds. He therefore studied the larynx, thevoice-producing organ, of a lamb. Soon hedeveloped a voice box that made different soundsusing levers. He also studied how the mouthchanges shape while making vowel sounds. Frombooks he came to know that a learned Germanscientist, Herman von Helmholz, had usedelectrically operated tuning forks to reproducecertain sounds of human speech.Graham Bell started his efforts in the direction of

the invention of telephone by attempting to developa "harmonic telegraph", a device that would allowseveral telegraph operators to send messages on


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the same wire at the same time. Thus he developedan idea for the telephone. By October 1874, Bell'sresearch had progressed to the extent that he couldinform his future father-in-law, Gardiner GreeneHubbard, about the possibility of a multipletelegraph. Hubbard resented the absolute controlon telegraph services exerted by the Western Union

T elegraph Company in USA at that time. He instantly saw in the Bell's efforts apotential forbreaking such a monopoly, so he gave Bell thefinancial backing he needed. Bell proceeded withhis work on the multiple telegraph. But he did notreveal to Hubbard that he and Thomas Watson, ayoung electrician whose services he had enlisted,were also exploring an idea that had occurred tohim that summer. The idea was to develop a devicethat would transmit speech electrically. They wereworking on a device that used steel reeds that couldbe set in vibration by electromagnets. One day

Watson tightened an adjustment screw of his devicea little too much. This prevented the reed fromvibrating, so he plucked the reed to try to set it inmotion again. Bell sitting in another room next tohis instruments heard a sound coming from thereeds in the device near him. He rushed to Watsonto find how it happened. What excited him the mostwas the fact the sound was not produced by an onand off electric current as was the case with electrictelegraph it was a continuous sound. Soonthereafter Bell experimented with vibratingmembranes instead of reeds. He was prompted todo so by his knowledge of the human ear. Within a

few weeks he was successful in transmitting thesounds of human voice through system that wascomposed of a microphone and a speaker. Themicrophone was like a funnel. One end open theother end pointing to a membrane connected to arotor that had to follow the vibrations of themembrane. This vibrating rotor was connected to acoil to induce an electric current that couldreproduce the voice sent into the funnel. Bell'smicrophone changed sound waves into an electriccurrent whose intensity changed quickly. Theelectric current can travel much faster and it iseasier to transmit it across long distances thansound.Graham Bell was not the only person who wastrying on such an idea. Another American inventor Elisha Gray was working on similar lines. In fact healso smelt success just at the same time. But onFebruary 14 1876 when Bell's father in law filed anapplication for the preliminary patent of Bell'sinvention, Elisha Gray was just a few hours too late.Nevertheless Bell had to face many problemssimilar to the ones faced by many other inventorsat that time. Nobody was initially interested in hisinvention. When he offered his patent for 100,000

American Dollars, the response was "What shall wedo with a toy like that?" This occurred in 1877. Thetelephone invented by Graham Bell was not


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immediately accepted for conversation, it was morecommonly used to send and listen to music. Butafter some improvements it became popular forconversations. TelevisionT elevision was not invented by one inventor, manyinventors from various parts of the worldcontributed. Therefore, its story is to be told slightly

differently.T elevision, in a way, is an extension of our sense ofvision. The process of televising a visual consists ofthree steps. Seeing it through a camera;transmitting it to remote places and finallyproducing its image on the screen of a TV. Thecamera used for television is different from aphotography camera. A photography camera cannotbe used for televising because it does not produceany electrical signals. Finding a method to convertthe image of a visual into a electric current wasindeed the first challenge for the potential inventors

of television. The discovery that led to the inventionof television was the discovery of the chemicalelement Selenium. A Swedish scientist, JacobBerzelius, discovered it in the early nineteenthcentury. It produces an electric current when lightfalls on it and is therefore called a photosensitiveelement (photo = light). This discovery led toinvention of several devices that could convert animage into an electric current and reproduce theimage. One such device was invented by a Germanengineer, Paul Nipkow, in 1884. This device theNipkows disk was an electromechanical device,and hence was not very successful.

For the later developments it was necessary toknow what exactly is an electric current. Nobodyknew it till 1897! Electric current became known tobe a flow of electrons after an English scientist, J.J.Thomson, discovered electrons -- the tiny negativelycharged particles in atoms. The invention ofcathode ray tube (CRT) by a German scientist, Karl Ferdinand Braun, was perhaps crucial for thedevelopment of an electronic television. In 1897,after electrons had been discovered Braun, likemany other scientists of the day was intrigued.Braun discovered that a stream of electronsemanating from a negatively charged electrode(cathode) inside a glass tube from which most ofthe air had been removeda cathode ray tube(CRT)could be focused to a point at the end of thetube. If the end of the tube were coated with afluorescent material, it would glow wherever thestream of electrons hit it. Braun also used a magnetoutside the tube, which interacted with theelectrons in the beam to move it back and forth. Bymoving the magnet, he could trace patterns on thescreen. Braun also used a magnet outside the tube,which interacted with the electrons in the beam tomove 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


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scanned, read like the text written on a paper, bymoving its beam over each point of the image.Cathode rays were moved using electromagnetsbecause it was already known that the strength ofan electromagnet can be varied by changing theelectric current flowing through it. Scanning animage to produce electric signal was therefore now

possible. Inventors tried coating the screen of a CRTwith selenium and found that the characterstics ofelectric currentproduced depends onthe image focussedon the screen. Thefirst electronic devicethat was close to themodern TV wasinvented by a Russianinventor, Vladimir Zworykin, in 1923. He called it iconoscope, it laidthe foundations for early television cameras.

However, the inventor who is most often creditedfor the invention of television is John Logie Baird, aScottish engineer. He achieved the transmission ofsimple face shapes in 1924 using Nipkows disc.Baird demonstrated 'television' publicly in Londonon March 25, 1925.The details of a scenein front of the cameracan be transmittedeither throughwireless transmitters (very similar to thoseused for broadcasting

sounds) or through acablelike telephone.An image of thescene can be produced on the screen of a televisionset by feeding into its CRT the electrical signalreceived. The main difference between the picturetube of a television set and that used in a televisioncamera is the coating on their screens, while aphotoconducting material, say, selenium, is used forcoating 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 phosphorproduces a dot of light when cathode rays fall on it.This light lasts only a fraction of second. Such lightdots produce a transient image on the screen. Asequence of such transient images produces amovie.CameraThe earliest form of a camera is often called"Camera Obscura". A Chinese philosopher Mo-Ti(5th century BC) was perhaps the first person tomention this type of device. He formally recordedthe creation of an inverted image formed by lightrays passing through a pinhole into a darkenedroom. He called this darkened room a "collectingplace" or the "locked treasure room." Aristotle (384-

322 BC), a famous Greek philosopher, alsounderstood the optical principle of the "cameraobscura". He viewed the crescent shape of a


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partially eclipsed sun projected on the groundthrough the holes in a sieve, and the gaps betweenleaves of a plane tree.The earliest "Camera Obscuras" were large roomsthat were used to observe a solar eclipse. A convexlens was used into the aperture in the 16th centuryto improve the image quality; a mirror was added to

reflect the image down onto a viewing surface. Thisdevice was often used as an aid for drawing forartists. Soon thereafter, in 1807, another kind ofcamera known as "Camera Lucida" was invented.No darkroom was needed for this kind of camera.The paper was laid flat on the drawing board, andthe artist would look through a lens containing theprism, so that he could see both the paper and afaint image of the subject to be drawn. He wouldthen fill in the image.Obtaining a direct recording of an image that didnot require the skills of an artist was not possible till

certain chemical substances that changed theirproperties when they are exposed to light becameknown. A German scientist discovered in 1727 thatif he mixes three chemicals: chalk, nitric acid, andsilver in a flask, the side of the flask facing sunlightgets darkened. In 1800, a scientist from England,Thomas Wedgwood, made the first "sun pictures" by placing opaque objects on leather treated with achemical called silver nitrate. However, thesepictures survived only under candles light, underany stronger source of light they detoriated veryfast. It was not until 1826 when a French scientistNicphore Nipce, combined the camera obscura

with photosensitive paper that it was possible toobtain a permanent image. Soon thereafter, in1834, another English scientist, Henry Fox T albot,used paper impregnated with silver nitrate or silverchloride. When exposed in a camera, this paperturned black where light struck it, creating anegative image of the subject. This was madepermanent by fixing with hypo. The images soobtained were of course only black and white. (Thestory of development of photography is very aptlydetailed on the websitehttp://www.scphoto.com/html/history.html.)These early development led to many otherdiscoveries and inventions that made it possible fornewspapers to carry photographs by 1880. Wayback in 1900 one could purchase a camera andshoot pictures using photography films produced bythe company Eastman Kodak.ElectricityA Greek philosopher Thales of Miletus, who livedabout 600 BC, is said to have discovered that amberacquires a power to attract light objects whenrubbed. Another Greek philosopher, Theophrastus,in a treatise written about three centuries later, toldthat some other substances also possess this power.Similarly, ancient Greeks as well as Chinese knew

magnets. But, it was not until AD 1600, when anEnglish physician William Gilbert studied both ofthem in detail and his observations were available


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in printed form, that the facts about electricity andmagnetism became widely known. Gilbert was thefirst person to apply the term electric (Greekelektron, "amber") to the force that such substancesexert after rubbing. He also distinguished betweenmagnetic and electric action.The first machine for producing an electric charge

was invented in 1672 by a German scientist Ottovon Guericke. It consisted of a sulfur sphere turnedby a crank on which a charge was induced when thehand was held against it. The French scientistCharles Francois de Cisternay Du Fay was the first todiscover that there are two different types ofelectric charge: positive and negative. The earliestdevice to store electric charge, the Leyden jar, wasinvented in 1745 at the University of Leiden in theNetherlands. It consisted of a glass bottle withseparate coatings of tinfoil on the inside andoutside. One sensed a violent shock by touching

both coatings of the foil simultaneously.Benjamin Franklin, an American scientist, spentmuch time to study electricity. Through his famouskite experiment he discovered that the atmosphericelectricity that causes the phenomena of lightningand thunder is identical with the electrostaticcharge on a Leyden jar. Franklin suggested thatelectricity is a "fluid" existing in all matter, and that its effects can be explained by excesses andshortages of this fluid.Alessandro Volta, an Italian scientist invented thefirst device capable of producing an electric current(electricity), a battery. He found that if pieces of two

different metals were separated with a cardboarddisk soaked in brine (salt solution), an electriccurrent flows through the wires connected to thesemetal pieces. In 1800, he announced a newelectrical device, the Voltaic Pile. This device wasmade of alternating disks of zinc and copper witheach pair separated by brine soaked cloth. This wasthe first battery.In 1831 Michael Faraday, a British scientistdiscovered the electromagnetic induction. This is amethod for producing a steady electric current.Faraday attached two wires through a slidingcontact to a copper disc. By rotating the discbetween the poles of a horseshoe magnet heobtained a continuous direct current. This was thefirst electric generator; it led to the establishment ofthe first electric power station in 1888.Blood groups

T e true nature and function of blood have beenshrouded in mystery ever since the beginning ofhistory. Using human blood to treat disease andtrauma had its beginnings in 1667 in France, whenJean-Baptiste Denis documented a direct humanblood transfusion. This was a scant forty years afterWilliam Harvey discovered the circulatory system.

These early direct donor-to-patient transfusionswere, however, frequently disastrous because itwas not possible to predict donor-recipient blood


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type compatibility.Experiments with blood transfusions, the transfer ofblood or blood components into a person's bloodstream, have been carried out for hundreds ofyears. Many patients died because of bloodtransfusions. Thus while in 1818, when JamesBlundell transfused blood to a woman from her

husband and it worked. But other patients died fromtransfusions. It was decades later when a Germannamed Leonard Landois learned why blood mixingcan be fatal: Sometimes it makes red blood cellsclump and explode.In 1901-1903 Landsteiner pointed out that asimilar reaction may occur when the blood of onehuman individual is transfused, not with the bloodof another animal, but with that of another humanbeing, and that this might be the cause of shock,jaundice, and haemoglobinuria that had followedsome earlier attempts at blood transfusions.

His suggestions, however, received little attentionuntil, in 1909, he classified the bloods of humanbeings into three blood groups A, B, and C. Theseeventually became known as A, B, and O. The rarergroup AB was not discovered until the followingyear by two of Landsteiner's pupils. These groupsare now well-known as A, B, AB, and O groups. Landsteiner showed that transfusions betweenindividuals of groups A or B do not result in thedestruction of new blood cells and that thiscatastrophe occurs only when a person istransfused with the blood of a person belonging toa different group.

Karl Landsteiner's work made it possible todetermine blood types and thus paved the way forblood transfusions to be carried out safely. For thisdiscovery he was awarded the Nobel Prize inPhysiology or Medicine in 1930. Later in 1940Landsteiner and Weiner made observations whichlaid the foundations of our knowledge about theremaining major blood group - the Rhesus system.Once reliable tests for Rhesus grouping had beenestablished, deaths due to blood transfusionbecame rare.PrintingWritten language is unquestionably one of the mostimportant human achievements therefore the abilityto reproduce written materials quickly andefficiently ranks not far behind. Only when writtenworks could be duplicated in quantities and speedsexceeding those achievable through laborioushandwritten copies did writing become a mediumfor the widespread dissemination of knowledgethemore copies of material available, the more peoplewho have access to them, the more likely thespread of literacy. The challenge, particularly incivilizations with large, complex systems of writing,was to develop a method for quickly and efficientlyarranging those symbols, using the arrangement to

create printed material, then re-arranging thesymbols for further use. Chinese printers were thefirst to structure printing in a way that hinted at


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mass-production in the 8th century. They usedwooden blocks with characters carved into them,which were then inked and stamped on paper.Extending the Chinese monopoly on printing, in the11th century Pi Sheng created a primitive form ofmoveable type (made of wood), which allowed forthe letters to be rearranged. In a neighboring

country Korea, moveable metal type was tried in theearly 15th century but it was not very successfuldue to the large number of characters in Koreanscript. In Europe printing developed a bit later. Tillthe beginning of the 15th century, they followed themethod introduced by Chinese -- block printing.As the methods for casting metals became known,the invention of a machine to print becamepossible. An innovator in Germany, JohannGutenberg spent over ten-years developing thewestern-style moveable type. He then developeda method using lead and tin alloys to mold

moving type for individual letters of the Roman script. He also inventeda machine, the printingpress that was based on the design of presses usedby farmers to make olive oil. The first printing pressused a heavy screw to force a printing block againstthe paper below and the ink used was a mixture ofturpentine, lampblack and linseed oil. Invented by1450 such a printing press made the masspublication and circulation of literature easy andeconomical. In the later models, as machinesbecame more popular, inking was carried out byrollers. These rollers would pass over the face of thetype and move out of the way onto a separate ink-

bed to pick up a fresh film of ink. A sheet of paperwas slid against a hinged plate, which was rapidlypressed onto the type and then swung back,allowing it to be removed and the next sheetinserted in its place.BacteriaBacteria are the most abundant of all organisms.They are ubiquitous in soil and water. Bacteriaconsist of only a single cell, but they are anamazingly complex and fascinating group ofcreatures. When most people think of bacteria, theythink of disease-causing organisms. But that isstrictly not true. Several kinds of bacteria areextremely helpful to us, they help us makemedicines or cook food.Antony van Leeuwenhoek, the man who discoveredbacteria, was neither a physician nor a universityprofessor but a Dutch draper and part-time janitorwho liked to look at things under a microscope.Leeuwenhoek came from a family of tradesmen,had no fortune, received no higher education oruniversity degrees, and knew no languages otherthan his native Dutch. This would have beenenough to exclude him from the scientificcommunity 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 themost important discoveries in the history of biology.


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It was he who discovered bacteria.Leeuwenhoek's skill at grinding lenses, togetherwith his naturally acute eyesight and great care inadjusting the lighting where he worked, enabledhim to build microscopes that magnified over 200times, with clearer and brighter images than any ofhis colleagues could achieve. What further

distinguished him was his curiosity to observealmost anything that could be placed under hislenses, and his care in describing what he saw.Although he himself could not draw well, he hiredan illustrator to prepare drawings of the things hesaw, to accompany his written descriptions. Most of his descriptions of microorganisms are instantlyrecognizable.In 1673, Leeuwenhoek began writing letters to thenewly formed Royal Society of London, describingwhat he had seen with his microscopes -- his firstletter contained some observations on the stings of

bees. For the next fifty years he corresponded withthe Royal Society; his letters, written in Dutch, weretranslated into English or Latin and printed in thePhilosophical Transactions of the Royal Society, andoften reprinted separately. RocketRocket is an indispensable tool in the exploration ofspace. T oday's rockets are remarkable collections ofhuman ingenuity that have their roots in the scienceand technology of the past.One of the first devices to successfully employ theprinciples essential to rocket flight was a woodenbird. The writings of Aulus Gellius, a Roman, tell astory of a Greek named Archytas who lived in the

city of T arentum, now a part of southern Italy.Somewhere around the year 400 B.C., Archytasmystified and amused the citizens of T arentum byflying a pigeon made of wood. Escaping steampropelled the bird suspended on wires. The pigeonused the action-reaction principle, which was notstated as a scientific law until the 17th century.About three hundred years after the pigeon,another Greek, Hero of Alexandria, invented asimilar rocket-like device called an aeolipile. It, too,used steam as a propellant.Hero mounted a sphere on top of a water kettle. Afire 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 sphereallowed the gas to escape, and in doing so gave athrust to the sphere that caused it to rotate.No one is really sure when the first true rocket wasbuilt. Stories of early rocket-like devices appearsporadically through the historical records of variouscultures. Perhaps the first true rockets wereaccidents. In the first century A.D., the Chinesereportedly had a simple form of gunpowder madefrom saltpeter, sulfur, and charcoal dust. T o createexplosions during religious festivals, they filled

bamboo tubes with a mixture and tossed them intofires. Perhaps some of those tubes failed to explodeand instead skittered out of the fires, propelled by the gases and sparks produc


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ed by the burninggunpowder.Chinese began experimenting with the gunpowderfilled tubes. At some point, they attached bambootubes to arrows and launched them with bows. Soonthey discovered that these gunpowder tubes couldlaunch themselves just by the power produced from

the escaping gas. The true rocket was born.The date reporting the first use of true rockets wasin 1232. At this time, the Chinese and the Mongolswere at war with each other. During the battle ofKai-Keng, the Chinese repelled the Mongol invadersby a barrage of "arrows of flying fire." These fire-arrows were a simple form of a solid-propellantrocket. A tube, capped at one end, containedgunpowder. The other end was left open and thetube was attached to a long stick. When the powderwas ignited, the rapid burning of the powderproduced fire, smoke, and gas that escaped out the

open end and produced a thrust. The stick acted asa simple guidance system that kept the rocketheaded in one general direction as it flew throughthe air. Although one may not be sure how effectivethese arrows of flying fire were as weapons ofdestruction, but their psychological effects on theMongols was formidable.Following the battle of Kai-Keng, the Mongolsproduced rockets of their own and may have beenresponsible for the spread of rockets to Europe. Allthrough the 13th to the 15th centuries there werereports of many rocket experiments. In England, amonk named Roger Bacon worked on improved

forms of gunpowder that greatly increased therange of rockets. In France, Jean Froissart found thatmore accurate flights could be achieved bylaunching rockets through tubes. Froissart's ideawas the forerunner of the modern bazooka. Joanesde Fontana of Italy designed a surface-running rocket-powered torpedo for setting enemy ships onfire.By the 16th century rockets were mainly used forfireworks displays, and a German fireworks maker,Johann Schmidlap, invented the "step rocket," amulti-staged vehicle for lifting fireworks to higheraltitudes. A large sky rocket (first stage) carried asmaller sky rocket (second stage). When the largerocket burned out, the smaller one continued to ahigher altitude before showering the sky withglowing cinders. Schmidlap's idea is basic to allrockets today that go into outer space.Nearly all uses up to this time were for warfare orfireworks, but there is an interesting old Chineselegend that reported the use of rockets as a meansof transportation. With the help of many assistants,a lesser-known Chinese official named Wan-Huassembled a rocket- powered flying chair. Attachedto 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


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India repulsed the British with rockets. During the19th century, rocket enthusiasts and inventorsbegan to appear in almost every country. By theend of the 19th century, soldiers, sailors, practicaland not so practical inventors got interested inrocketry. Skillful theorists, like KonstantianT siolkovsky in USSR, studied the science behind

rocketry. They also examined the possibility ofspace travel. Three persons were particularlysignificant in the transition from the small rockets ofthe 19th century to the giant rockets of today. Theywere: Konstantin T siolkovsky from Russia, RobertGoddard from the United States, and HermannOberth from Germany. CellsMost cells are too small, they cannot be observedwith the naked eye. It is for this reason that theexistence of cells escaped notice until scientists firstlearned to harness the magnifying power of lensesin the second half of the seventeenth century, that

is the invention of the microscope. A Dutch clothingdealer named Antonie van Leeuwenhoek inventedthe single-lens microscopes. Gazing into the lens ofthese microscopes, he discovered single-celledorganisms, which he called "animalcules" andwhich, today, we call bacteria and protists.Englishman Robert Hooke expanded onLeeuwenhoeks observations with the newlydeveloped compound microscope, which uses twoor more aligned lenses to increase magnificationwhile reducing blurring. When Hooke turned themicroscope on a piece of cork, he noticed that thetiny, boxlike compartments of the wood resembled

the cells of a monastery. The term 'cell' was born.As microscope technology improved, scientists wereable to study cells in ever-greater detail. Hooke hadno way to tell if cells were living things, but laterresearchers who could see the nucleus and theswirling motion of the cytoplasm were convincedthat cells were indeed alive. By 1839, enoughevidence had accumulated for German biologistsMatthias Schleiden and Theodore Schwann toproclaim that cells are the elementary particles ofall biological organisms. But many scientists still did not believe that cells arose from other cells until1855, when a famous German scientist RudolphVirchow pronounced, "All cells come from cells."Nearly 200 years after the discovery of cells, theobservations of Virchow, Schleiden, and Schwannestablished the cell theory. According to this theory:All living things are made of cells and all cells arisefrom preexisting cells.AntibioticsThe use of antibiotics is often considered one of thewonders of the modern world. It has had dramaticeffects on the practice of medicine, thepharmaceutical industry, and microbiology. Prior tothe discovery of antibiotics, the treatment ofinfectious diseases was not very scientific. Various

types of antimicrobial agents, including extracts ofplants, fungi, and lichens, were employed forthousands of years in primitive populations without


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any scientific knowledge of what was being used.Even in the early part of the twentieth century,therapy for infectious diseases was basedessentially on patient isolation and chicken soup.The search for antibiotics began in the late 1800s,with the growing acceptance of the germ theory ofdisease, a theory, which linked bacteria and other

microbes to the causation of a variety of ailments.As a result, scientists began to devote time tosearching for drugs that would kill these disease-causing bacteria. The goal of such research was tofind so-called magic bullets that would destroymicrobes without toxicity to the person taking thedrug.One of the earliest areas of scientific exploration inthis field was whether harmless bacteria could treatdiseases caused by pathogenic strains of bacteria.By the late 19th century there were a few notablebreakthroughs. In 1877, Louis Pasteur showed that

the bacterial disease anthrax, which can causerespiratory failure, could be rendered harmless inanimals with the injection of soil bacteria. In 1887,Rudolf Emmerich showed that cholera wasprevented in animals that had been previouslyinfected with the streptococcus bacterium and theninjected with the cholera bacillus.In the early 1920s, the British scientist AlexanderFleming reported that a product in human tearscould brealdown (lyse) bacterial cells. Soon hemade another discovery that changed the course ofmedicine. In 1928, Fleming discovered anotherantibacterial agent. He named this substance

penicillin after the Penicillium mold that hadproduced it. By extracting the substance fromplates, Fleming was able to show its effects;penicillin destroyed a common bacterium,Staphylococcus aureus, associated with sometimesdeadly skin infections.PetroleumPetroleum is one of the most important sources ofenergy today. But for petrol and diesel, fuelsextracted from petroleum travel would be anightmare. Petroleum is often food deep under theEarth surface. The first oil wells to extractpetroleum were drilled in China in the 4th centuryor earlier. They were up to 800 feet deep and weredrilled using bits attached to bamboo poles. The oilwas burned to evaporate seawater and producesalt. By the 10th century, extensive bamboopipelines connected oil wells with salt springs.Ancient Persian tablets indicate the medicinal andlighting uses of petroleum in the upper echelons oftheir society.In the 8th century, the streets of the newlyconstructed Baghdad were paved with tar, derivedfrom easily-accessible petroleum from natural fieldsin the region. In the 9th century, oil fields wereexploited in Baku, Azerbaijan, to produce naphtha.

The geographer Masudi in the 10th century, and byMarco Polo in the 13th century, described thesefields whose output was hundreds of shiploads.


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The modern history of oil began in 1853, with thediscovery of the process of oil distillation. Crude oilwas distilled into kerosene by Ignacy Lukasiewicz, aPolish scientist. The first "rock oil" mine was createdin Bobrka, near Krosno in southern Poland in thefollowing year and the first refinery (actually adistillery) was built in Ulaszowice, also by

Lukasiewicz. These discoveries rapidly spreadaround the world, and Meerzoeff built the firstRussian refinery in the mature oil fields at Baku in1861.The first modern oil well was drilled in 1848 bya Russian engineer F .N. Semyenov, on the AspheronPeninsula north-east of Baku.By 1910, significant oil fields had been discoveredin Canada (specifically, in the province of Alberta),the Dutch East Indies (1885, in Sumatra), Persia(1901, in Masjed Soleiman), Peru, Venezuela, andMexico, and were being developed at an industriallevel. The Indian petroleum industry dates back to

1890 when oil was first struck at Digboi innortheastern India. However, the most significantdiscovery of petroleum in India was that at BombayHigh, on 19th February 1974, which, in reality, wasthe turning point in history of oil exploration inIndia.OxygenOxygen supports all life on Earth and is essential forcombustion and respiration, yet its very existencewas not known until the 1770's, when scientistsbegan to concern themselves with air and how itaffects combustion. The ancient Greeks consideredair to be an element composed of a singlesubstance, and this view persisted through the

centuries. The discovery of oxygen, its significance,and the capability for measuring it accuratelyrequired some major scientific breakthroughs.In 1770, G.E. Stahl, a German physician, proposed atheory that received widespread acceptance. Heclaimed that all inflammable objects contained amaterial substance that he called "phlogiston," froma Greek word meaning "to set on fire." When anobject burned, it poured its content of phlogistoninto the air, and when all its phlogiston was gone, itstopped burning. Wood lost its phlogiston veryrapidly, so that its passage into air was visible asflames. Stahl suggested that the rusting of metalsalso depended on the loss of phlogiston tosurrounding air, except that metals lost theirphlogiston so slowly that rusting was a gradualprocess.Experiments to learn more about the principles ofcombustion were made in 1772 by a Scottishchemist, Joseph Black, and his student, DanielRutherford. They tried burning candles in closedcontainers of air and found that the candleseventually went out even though the containers stillheld a large amount of air. Mice put into thesecontainers promptly died. Holding to the phlogiston

theory, Rutherford came to the conclusion that theburning candles emitted phlogiston but a givenvolume of air could hold only a certain amount of


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phlogiston. When the saturation point was reachedin the closed container, the air would not accept any more phlogiston and the candle would go outbecause it could not continue to emit phlogiston.Rutherford believed that, in like manner, a livingcreature gives up phlogiston while breathing andwhen placed in air that is already saturated with

phlogiston, can no longer breathe and must die.The demolition of the phlogiston theory began withexperiments carried on in 1774 by Joseph Priestly,an English clergyman who was interested inscience. His experiments involved the heating ofmercury by exposing it to sunlight concentratedthrough a magnifying glass. The heated mercurybecame coated with a reddish powder, whichPriestly reheated at a higher temperature. Thepowder evaporated and turned into two gases, oneof which was mercury vapor. The mercury vaporcondensed into drops of mercury in the test vessel

as it cooled. The other gas was invisible, butPriestly knew it existed because when he placed asmoldering splint of wood into it, the wood burstinto flame, and mice put into this invisible gasbecame hyperactive. Priestly stuck to thephlogiston theory to explain these results. Hethought that heated mercury lost some of itsphlogiston and turned into mercury rust. When thisrust was heated, it absorbed phlogiston from air andturned back into mercury. The invisible gas hadalso lost its phlogiston, and it drew phlogistonrapidly from the smoldering wood splint, causingthe splint to burst into flame.

Priestly later traveled to Paris, where he discussedhis experiments with a brilliant French chemist,Antoine Lavoisier, who had been carrying on hisown experiments in combustion. Lavoisier'sexperiments had convinced him that phlogiston didnot exist and combustion was caused by thecombination of fuel with air. However, he wasunable to prove his theory until Priestly describedhis experiments with heated mercury. Lavoisier had burned candles in closed containers and he hadobserved that only one-fifth of the air wasconsumed during burning and the remaining four-fifths would not support combustion. After hisdiscussions with Priestly, Lavoisier realized thatwhat Priestly called two different kinds of air - onewith phlogiston and one without - was really onlyone kind of air that contained two substances.Lavoisier called the one-fifth of the air thatsupported combustion "oxygen" (from the Greekwords meaning "acid-producing," because hethought (wrongly) that oxygen was a necessarycomponent of all acids). The four-fifths of the airthat does not support respiration or combustion hecalled "azote" (from the Greek words meaning "nolife"). Azote today is known as "nitrogen.Paper

Nobody knew paper 1900 years ago! A Chinese,T'sai Lun, invented paper in 105 AD. Heexperimented with a wide variety of materials and


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refined the process of macerating the plants fibersuntil each filament was completely separate. Theindividual fibers were mixed with water in a largevat and then a screen was submerged in the vatand lifted up through the water, catching the fiberson its surface. When dried, this thin layer ofintertwined fiber became paper. T'sai Lun's thin, yet

flexible and strong paper with its fine, smoothsurface was known as T'sai Ko-Shi , meaning:"Distinguished T'sai's Paper" and he became thepatron "saint of papermaking". It took about ahundred years for the use of paper to spread acrosscentral Asia. Books followed soon after. T o producebooks required printing. The very first books wereprinted in China, by stamping of seals (somethinglike rubber stamps used nowadays) on paper.The utility of books prompted people to improve thetechnique of making paper. The pioneers of thisventure were mostly the Asians. Japanese

discovered a method to make paper from wastepaper. Egyptians used cloth rags to make paper.This knowledge gradually made its way to thewestern countries through the Muslim world - toBaghdad, Damascus and Cairo and ultimately toEurope in the 12th century.The Europeans quickly grasped the merits ofprinting on paper. They improvised methods formaking paper on a large scale. The earliest paper inEurope was made from recycled cotton and linen.This was an impetus for the trade of old rags. Whenthis source became insufficient curious attemptswere made to source new materials - the most

macabre of which was the recycling of Egyptianmummies to create wrapping paper! They alsoexperimented with fibers such as straw, cabbage, wasp-nests and finally wood. Ultimately this questended when inexpensive and replaceable materialsfor papermaking-the long soft fibers of softwoodssuch as spruce, were discovered. A paper mill, thatis an industry to produce paper on a large scale,was established for the first time in England in theyear 1495.RefrigeratorRefrigeration is the process by which heat from anenclosed space, or from a substance is removedand transferred to lower its temperature. Arefrigerator uses the phenomenon of evaporation ofa liquid to absorb heat. The liquid, or refrigerant,used in a refrigerator evaporates at an extremelylow temperature, creating freezing temperaturesinside the refrigerator.Before the invention of refrigerator, people cooledtheir food with ice and snow, either found locally orbrought down from the mountains. The first cellarswere holes dug into the ground and lined with woodor straw and packed with snow and ice: this was theonly 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 energyand draws the energy needed from the immediate


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area - which loses energy and becomes cooler.Cooling caused by the rapid expansion of gases isthe primary means of refrigeration today.William Cullen at the University of Glasgow wasperhaps the first inventor who demonstrated arefrigerator in 1748. However, he did not use hisdiscovery for any practical purpose. In 1805, an

American inventor, Oliver Evans, designed the firstrefrigeration machine. Jacob Perkins built the firstpractical refrigerating machine in 1834; it usedether in a vapor compression cycle. An Americanphysician, John Gorrie, built a refrigerator based onOliver Evans' design in 1844 to make ice to cool theair for his yellow fever patients. German engineerCarl von Linden, patented not a refrigerator but theprocess of liquifying gas in 1876 that is part of basicrefrigeration technology.Till about 1929 refrigerators used the toxic gasesammonia (NH3), methyl chloride (CH3Cl), and sulfurdioxide (SO2) as refrigerants. Several fatal

accidents occurred in the 1920s when methylchloride leaked out of refrigerators. Three Americancorporations launched collaborative research todevelop a less dangerous method of refrigeration;their efforts lead to the discovery of Freon. In just afew years, compressor refrigerators using Freonbecame the standard for almost all home kitchens.Only decades later, would people realize that thesechlorofluorocarbons endangered the ozone layer ofthe entire planet.The Cell phoneThe basic concept of cellular phones began in 1947,when some engineers in USA looked at crudemobile (car) wireless phones that were used in USA

at that time. The number of the users of suchphones was very small because the number offrequencies available for them was limited. It wasrealized that if transmission of radio waves waslimited to a small area, small cells a frequency canbe reused in another remote cell, thus increasingthe traffic capacity of mobile phones substantially.However at that time, the technology to do so wasnonexistent.In USA, anything to do with wireless communicationis decided by a department known as FederalCommunications Commission (FCC). Since a cellphone is a type of two-way radio, in 1947, anAmerican company AT&T proposed that the FCCallocate a larger number of frequencies ofelectromagnetic waves capable of radiocommunication to make mobile telephone servicefeasible. But FCC declined this request.This position was reconsidered in 1968. AT&T and'Bell Labs' then proposed the present form ofcellular system. In this system many small, low-powered, broadcast towers, each covering a 'cell' afew kilometers in radius collectively cover a largearea. Each tower uses only a few of the totalfrequencies allocated to the system. As the phones

travel across the area, calls are passed from towerto tower.Dr Martin Cooper, a general manager at an


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American company 'Motorola', is considered theinventor of the portable cellphone handset. Coopermade the first call on a portable cell phone in April1973. He made the call to his rival, Joel Engel.Motorola was the first company to incorporate technology into portable device that was designedfor use even outside of an automobile. By 1977,

AT&T and Bell Labs had constructed a prototypecellular system.Pencil and PenThe Greeks introduced the earliest instrument ofwriting that approached the pen. They employed awriting stylus, made of metal, bone or ivory, toplace marks upon wax-coated tablets. The tabletsmade in hinged pairs, closed to protect the scribesnotes. Thus the first examples of handwriting(purely text messages made by hand) originated inGreece. A scholar from Greece, Cadmus inventedthe written letter - text messages on paper sentfrom one individual to another.

The instrument used for writing that dominated forthe longest period in history (over one-thousandyears) was the quill pen. Introduced around 700A.D., the quill was a pen made froma bird feather. The strongest quillswere those taken from living birdsin the spring from the five outer leftwing feathers. The left wing wasfavored because the featherscurved outward and away whenused by a right-handed writer.Goose feathers were mostcommon; swan feathers were of a

premium grade being scarcer andmore expensive. For making fine lines, crowfeathers were the best, followed by the feathers ofthe eagle, owl, hawk and turkey.Pencil was most likely invented in England, aftersome shepherds in Borrowdale found small piecesof a charred oak tree that had fallen during a storm,useful for marking sheep, sometime in 1564. Soonthereafter small pieces of this material wereencased in wood to produce a sturdy and cleanwriting instrument that needed no ink. Many peoplehave wondered why the core of a pencil is calledlead. The answer perhaps lies in the fact thatGreeks and Romans used small disc shaped pieces of lead to write, way back in 20B.C. Thats whymaterial discovered by shepherds was initiallyknown as plumbago (imitation Lead), until aSwedish scientist, W. Scheele, found it to be a formof carbon and gave it the name graphite (from theGreek word Graphis for writing). Fountain pensand the ballpoint pens came much later, the earliestsurviving fountain pens date to the early 18th (orpossibly later 17th) century; they are made ofmetal, or cut quills used as nibs. From the beginningof the 19th century, the number of fountain pen

designs patented and produced began to multiply.Three major advances paved the way for thefountain pens widespread acceptance: the


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invention of hard rubber (a naturally-derived plastic,resistant to chemicals, easily machined, andrelatively cheap); the availability of iridium-tippedgold nibs; and improved inks, not laden withclogging sediment. But, all these three factors fellinto place later, sometime around 1870 - 1880.Computer

The story of invention of computer differs from thestory of invention of television. It was invented notby any individual, rather through large commercialestablishments. Several groups of people workingfor a large business houses made it possible. Theearliest computer was somewhat like aprogrammable calculator; it could only makemathematical calculations. A German inventor,Konrad Zuse, is often credited with the invention ofthe first electronic computer is. He made the world'sfirst electronic, fully programmable digital computerin 1941, with recycled materials donated by his

colleagues in university. Five years later in 1946,John Mauchly and J Presper Eckert developed theENIAC I (Electrical Numerical Integrator AndCalculator) under a project sponsored by the U.S.military. This computer covered 167 square metersof floor space, weighed 30 tons, and consumed 160 kilowatts of electrical power.In one second, it couldperform 5,000 additions, 357 multiplications or 38divisions.Later computers became significantly smaller. Thisbecame possible due to the invention of a device,the transistor. Three American scientists, JohnBardeen, William Shockley, and Walter Brattain,

invented transistor while working for the BellT elephone Laboratories in U.S.A. (A business houseestablished by Graham Bell -- the inventor ofT elephone). They invented it accidentally whilestudying the behavior of crystals of germanium tofind something to replace vacuum tubes asmechanical relays in telecommunications. Thevacuum tubes, used at that time in various devicesfor communication, consumed lots of electricity andproduced unnecessary heat. A transistor is madefrom semi-conductor materials. A semiconductormaterial is a kind if material that can conductelectricity as well as stop its flow (insulator).Chemical elements germanium and silicon are twoexamples of semiconductor materials. A transistor isthe first device discovered to be capable of actingas a transmitter, converting sound waves intowaves of electric current, and a resistor, controllingelectric current. No doubt transistors soon replacedvacuum tubes in the computers. Computers madeup of transistors were more reliable and consumedmuch less electricity.The next step was the integration of many electricdevices into a tiny small crystal of silicon, anintegrated circuit (IC). Till 1959, it was believed that

to make a computer more efficient it is necessary toincrease the number of electrical components in it.After the invention of integrated circuits, hundred of


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transistors, resistors, capacitors and connectingwires, could be put into a single component -thechip. A chip is made on a single crystal of asemiconductor material. The technology for making an IC was invented by two American engineers JackKilby, working for a company named T exasInstruments and Robert Noyce, the co-founder of

the Fairchild Semiconductor Corporation. Furtherdevelopment of computer was due to thedevelopment of an IC specifically designed forcomputers. In 1971, a company Intel introduced amicroprocessor as an IC, the Intel 4004. Threeemployees of Intel are said to be responsible for theinvention of this chip: Federico Faggin, T ed Hoff, andStan Mazor. In this IC all the parts that made acomputer think (i.e. central processing unit,memory, input and output controls) are on a singlechip.The person who can perhaps be called the inventor

of personal computers is Douglas Engelbart. Heinvented or contributed to several interactivedevices and features: the computer mouse,windows, computer video teleconferencing, email,the Internet and more. However, the real revolutionin PC was the handiwork of a few computerwhizkids: Bill Gates and Steve Jobs who developedsoftware that is really user friendly.Electric lampThe story of the invention of electric lamp goesback to 1811, when Sir Humphrey Davy discoveredthat an electrical arc passed between two polesproduced light. In 1841, experimental arc lightswere installed as public lighting along the Place de

la Concorde in Paris. Other experiments wereundertaken in Europe and America, but the arc lighteventually proved impractical because it burned outtoo quickly. Inventors continued to grapple with theproblem of developing a reliable electric light thatwould be practical for both home and public use asa viable alternative to light from burning gas.However, the practical solution for producing lightfrom electricity lay not in an electrical arc in openspace, rather in electricity passed through afilament. The breakthrough theory became known,as the Joule effect after James Prescott Joule, whotheorized that electrical current, if passed through aresistant conductor, would glow white-hot with heatenergy turned to luminous energy. The problem wasdevising the right conductor, or filament, andinserting it in a container, or bulb, without oxygenbecause the presence of oxygen would cause thefilament to burn out.Sir Joseph Wilson Swan an English inventor was thefirst person to construct an electric light bulb, buthe had trouble maintaining a vacuum in his bulb.Thomas Alva Edison the legendary Americaninventor 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 hisassociates worked on at least three thousand


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different theories to develop an efficientincandescent lamp. Incandescent lamps make lightby using electricity to heat a thin strip of material (called a filament) untilit gets hot enough to glow.Many inventors had tried to perfect incandescentlamps to "sub-divide" electric light or make itsmaller and weaker than it was in the existing arc

lamps, which were too bright to be used for smallspaces such as the rooms of a house.Edisons lamp was made up of a filament inside in aglass bulb from which all air had been removed.Edison was targeting a high resistance system thatwould require far less electrical power than wasused for the arc lamps. He knew such small electriclights would be suitable for home use.By January 1879, at his laboratory in Menlo Park,New Jersey, Edison had built his first highresistance, incandescent electric light. It worked bypassing electricity through a thin platinum filament

in the glass vacuum bulb, which delayed thefilament from melting. Still, the lamp only burnedfor a few short hours. In order to improve the bulb,Edison needed all the persistence he had learnedyears before in his basement laboratory. He testedthousands and thousands of other materials to usefor the filament. He even thought about usingtungsten, which is the metal used for light bulbfilaments now, but he couldnt work with it giventhe tools available at that time.AutomobilesTransportation had changed very little between thetime of the Romans and the early 1800s. Peoplewalked, rode horses, or rode in slow vehicles pulled

by horses. At sea, people relied upon wind andmuscle power. The word Automobile means a self-propelled vehicle. Such vehicles do not need ananimal to move rather they depend on the energyin a fuel, say coal, petrol, diesel etc.Nicholas Cugnot, a French engineer in 1769,invented the first automobile. This automobile wasbased on a steam engine. It looked like a massivetricycle. This ancestor of automobiles can perhapsstill be seen in Paris. In 1873, Amedee Bollee,another Frenchmen invented an automobile thatwas called Obe`issant, a French word meaningobedient. It looked like a bus.However, steam engine proved impractical for amachine that was intended to challenge the speedof a horse-and-buggy. The invention of the practicalautomobile had to await the invention of a workableinternal combustion engine. An internal combustionengine in contrast to a steam engine that burns itsfuel outside the engine is any engine that uses theexplosive combustion of a liquid fuel to push apiston within a cylinder - the piston's movement.The most common internal combustion engine typeis gasoline powered. Others include those fueled bydiesel, turns a crankshaft that then turns the car

wheels via a chain or a drive shaft.Gottlieb Daimler and Wilhelm Maybach built thefirst automobile based on internal combustion


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engine in Germany in 1889. Powered by a 1.5 hp,two-cylinder gasoline engine, it had a four-speedtransmission and traveled at 10 mph. AnotherGerman, Karl Benz, also built a gasoline-poweredcar the same year. The gasoline-powered automobile, or motor car, remained largely acuriosity for the rest of the nineteenth century, with

only a handful being manufactured in Europe andthe United States.The first automobile to be produced in quantity wasthe 1901 Curved Dash Oldsmobile, which was builtin the United States by Ransom E. Olds. Modernautomobile mass production, and its use of themodern industrial assembly line, is credited toHenry Ford of Detroit, Michigan, who had built hisfirst gasoline-powered car in 1896. Ford beganproducing his Model T in 1908, and by 1927, when itwas discontinued; over 18 million had rolled off theassembly line.

Electric batteryA battery produces electricity using two differentmetals in a chemical solution. A chemical reactionbetween the metals and the chemicals frees moreelectrons in one metal than in the other. One end ofthe battery is attached to one of the metals; theother end is attached to the other metal. The endthat frees more electrons develops a positivecharge and the other end develops a negativecharge. If a wire is attached from one end of thebattery to the other, electrons flow through the wireto balance the electrical charge.There is evidence that primitive batteries were used

in Iraq and Egypt as early as 200 B.C. forelectroplating and precious metal gilding. In 1748,Benjamin Franklin coined the term battery todescribe an array of charged glass plates.Around the 1790s, through numerous observationsand experiments, Luigi Galvani, an Italian professor,caused muscular contraction in a frog by touchingits nerves with electrostatically charged metal.Later, he was able to cause muscular contraction bytouching the nerve with different metals without asource of electrostatic charge. He thought thatanimal tissue contained an innate vital force, whichhe termed "animal electricity."In fact, it was Volta's famous disagreement withGalvani's theory of animal electricity that led Volta,in 1800, to build the voltaic pile to prove thatelectricity did not come from the animal tissue butwas generated by the contact of different metals ina moist environment.Most historians attribute the invention of thebattery to Alessandro Volta since his voltaic pile wasthe first battery that produced a reliable, steadycurrent of electricity.Voltas inventionwas to give rise toelectrochemistry,

electromagnetismand the modernapplications of


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electricity. AlsoGalvani's idea ofanimal electricitywere not uselesseither. Galvanisresearch was soonto develop into

electrophysiologyand modern biology.LoudspeakerFrom time immemorial people have beencommunicating through sounds because it is one ofthe most efficient and economical means ofcommunication. However, sound produced by aperson has its limitations. It can only travel acertain distance, in other words it is sometimes notloud enough to reach the target. This need was themother of the invention of loudspeakers. Aloudspeaker is a type of transducer, i.e. it is adevice that can transform energy in one type of

wave, motion, signal, excitation or oscillation intoanother. Loudspeakers convert electrical energyinto mechanical energy, which in turn is convertedinto sound energy. Obviously a loudspeaker couldnot have been invented before electricity wasdiscovered and means for producing it invented.A loudspeaker is a type of transducer, i.e. it is adevice that can transform energy in one type ofwave, motion, signal, excitation or oscillation intoanother. Loudspeakers convert electrical energyinto mechanical energy, which in turn is convertedinto sound energy.Alexander Bell patented the first loudspeaker as

part of his telephone in 1876. Ernst Siemens, aGerman in 1878, soon invented an improvedversion. The modern design of moving-coilloudspeaker was established by Oliver Lodge, aphysicist and writer, involved the development ofthe wireless telegraph in 1898. He was also the firstperson to transmit a radio signal (in 1894, one yearbefore Marconi did so), and received internationalrecognition for his work. Since large powerfulpermanent magnets of the correct shape forloudspeaker construction were not freely availableat reasonable cost at that time, these loudspeakers,found in early radio systems, utilizedelectromagnets.The quality of sound produced from loudspeakersystems until the 1950s was rather poor.Developments in cabinet technology (e.g. acousticsuspension) and changes in materials used in theactual loudspeaker, such as the move away fromsimple paper cones, led to audible improvements.Paper cones (or doped paper cones, where thepaper is treated with a substance to improve itsperformance) are still in use today, and can providegood performance. Polypropylene and aluminiumare also used as diaphram materials.MicrophoneA microphone is a device that converts sound

waves into electricity. Microphones were first usedwith early telephones and then radio transmitters.In 1827, an English scientist ,Sir Charles


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Wheatstone, coin ed the phrase "microphone."In 1876, Emile Berliner invented the firstmicrophone used as a telephone voice transmitter.He had seen a Bell Company telephonedemonstration at the U.S. Centennial Exposition andwas inspired to find ways to improve the newlyinvented telephone. The Bell T elephone Company

was impressed with what the inventor came up withand bought Berliner's microphone patent for$50,000.In 1878 David Edward Hughes, invented the carbonmicrophone, which was later developed during the1920s. Hughes's microphone was the early modelfor the various carbon microphones now in use.With the invention of the radio, new broadcastingmicrophones were created. The ribbon microphonewas invented in 1942 for radio broadcasting.In 1964, Bell Laboratories researchers James Westand Gerhard Sessler received a patent for an

electret microphone. The electret microphone offersgreater reliability, higher precision, lower cost, anda smaller size. It revolutionized the microphoneindustry, with almost one billion manufactured eachyear.During the 1970's, dynamic and condenser micswere developed, allowing for a lower sound levelsensitivity and a clearer sound recording.Microwave ovenThe microwave oven is the first new method ofcooking since man invented fire. You may besurprised to know that no one ever set out todiscover the microwave oven. It was an accidentaldiscovery.

Way back in 1940, two scientists, Sir John Randalland Dr. H. A. Boot, invented a device called amagnetron to produce microwaves in their lab atEngland's Birmingham University. The magnetron isa radar (radio detecting and ranging) device thatbounces microwaves off the enemy's war machinesto detect their presence.In 1946, an American engineer named Dr. PercySpencer, a self-taught engineer was performingtests on a magnetron tube when he got strongcravings for the chocolate bar that was in hispocket. He reached into his pocket only to besurprised by a nice gooey mess. Doc Spencer waswell aware of the fact that the magnetron producedheat, but he did not sense any. However, hesuspected that the magnetron had melted thechocolate, not his body heat. He needed to test histheory that the magnetron was cooking his food. Hesent out for a bag of popcorn and placed it in frontof the magnetron tube. The popcorn popped allover the floor!! Next morning he tried cooking upsome eggs, one of his fellow colleagues was verycurious and happened to get a bit too close - theegg 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 hesucceeded in building the oven, but it was very


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large. After all, the 1940's were not known forminiaturization of electronics.Now, that we know the story of invention lets knowhow food is cooked in a microwave oven.Microwaves are a type of radio waves. They canpass through the outer layer of food (just as theypass through the walls of a house) and heat the

interior directly. They do this by setting molecules ofwater, fats, sugars, and other food components intorapid motion. Since a molecule in the middle of apiece of food can receivethis energy as readily asone on the exterior,microwaves are sometimessaid to cook food from theinside out. In practice,however, they are generallyabsorbed in the outer inchor so of a piece of food, which is why thick items

that are cooked in a microwave oven can still beraw inside. MagnetsThe most popular legend about the discovery ofmagnets is that of an elderly Cretan shepherdnamed Magnes. Legend has it that Magnes washerding his sheep in an area of Northern Greececalled Magnesia, about 4,000 years ago. Suddenlyboth, the nails in his shoes and the metal tip of hisstaff became firmly stuck to the large, black rock onwhich he was standing. T o find the source ofattraction he dug up the Earth to find lodestones(load = lead or attract). Lodestones containmagnetite, a natural magnetic material. This type

of rock was subsequently named magnetite, aftereither Magnesia or Magnes himself. People soonrealized that magnetite not only attracted objectsmade of iron, but when made into the shape of aneedle and floated on water, magnetite alwayspointed in a north-south direction creating aprimitive compass. This led to an alternative namefor magnetite, that of lodestone or "leading stone".For many years following the discovery of lodestonemagnetism was just a curious natural phenomenon.The Chinese developed the mariner's compasssome 4500 years ago. The earliest mariner'scompass comprised a splinter of loadstone carefullyfloated on the surface tension of water.Peter Peregrinus is credited with the first attempt toseparate fact from superstition in 1269. Peregrinuswrote a letter describing everything that wasknown, at that time, about magnetite. However,significant progress was made only with theexperiments of William Gilbert in 1600 in theunderstanding of magnetism. It was Gilbert whofirst realized that the Earth was a giant magnet andthat magnets could be made by beating wroughtiron. He also discovered that heating resulted in theloss of induced magnetism.In 1820 Hans Christian Oersted, a scientist from

Danemark, demonstrated that magnetism wasrelated to electricity by bringing a wire carrying anelectric current close to a magnetic compass which


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caused a deflection of the compass needle. Thislead to the knowledge that whenever current flowsthere is be an associated magnetic field in thesurrounding space, or more generally that themovement of any charged particle will produce amagnetic field. Electric motorA broad definition of "motor" would be: any device

that converts electrical energy into motion. As is sooften the case with inventions, the credit fordevelopment of the electric motor belongs to morethan one individual. It was through a process ofdevelopment and discovery beginning with HansOersted's discovery of electromagnetism in 1820and involving additional work by William Sturgeon,Joseph Henry, Andre Marie Ampere, MichaelFaraday, and a few others.The story of invention of electric motor dates backto 1831, when an American physicist Joseph Henrypublished an article in a science journal, describing

a device that was basically the reverse of theelectric generator. Instead of converting mechanicalmovement into an electric current, like thegenerator, his device used electric current toproduce mechanical movement. Henry's motor wasthe first to be constructed, although inefficiencylimited its potential. In 1834 American blacksmithThomas Davenport improved the motor's operatingprinciples, using four magnets, two fixed and tworevolving. Davenport used his motor to operate hisown drills and wood-turning lathes. He went on toincorporate his motor in the electric railway,electric trolley, electric piano, and electric printing

press.Meanwhile the English inventor scientist, MichaelFaraday, had been making advances of his own.Faraday, having learned of Hans Christian Oersted'sdiscovery that an electric current created amagnetic field, which could deflect a compassneedle, set out to reverse the results and create anelectric 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 thepool. When a current was passed through the wire,the wire rotated around the magnet. This motor isoften demonstrated in school physics classes, butbrine is sometimes used in place of the toxicmercury. This is the simplest form of a class ofelectric motors called homopolar motors.The modern DC motor was invented by accident in1873, when Znobe Gramme, a Belgian electricalengineer, connected a spinning dynamo to asecond similar unit, driving it as a motor.AirplaneMen have dreamed of being able to fly for centuries.Leonardo da Vinci (1452-1519) imagined devicesthat would enable human beings to fly and drewpictures of such machines. In 1782 the Montgolfier

brothers invented a hot air balloon that floated overParis for 25 minutes. The development of poweredballoons, however, did not lead to practical aircraft.


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Around the turn of the twentieth century, dozens ofpeople were working to invent the airplane. Theperiod of active experimentation begins in 1891,when noted German engineer Otto Lilienthal beganexperimenting with hang gliders. Lilienthal tookseriously the ideas advocated by Sir George Cayleyalmost a hundred years earlier. Through an

extensive study of birds and bird flight, Cayleyrealized that the lift function and the thrust functionof bird wings were separate and distinct, and couldbe imitated. Following in Lilienthal's footsteps,efforts to invent an airplane became commonplacein Europe. Although an occasional aircraft flewfarther than 100 meters (about the length of afootball field), this level of performance wasexceptional. It was at such a juncture that thelegendary 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 afew months, the Wright brothers built and flewseveral kites, testing and perfecting their new ideasabout a flight control system. In 1900, they usedthis system on a man-carrying glider for the firsttime. Before they risked their own necks, they flewthe glider as a kite, controlling it from the ground.They flew three biplane (has two wings, one abovethe other) gliders and by 1902 they had developeda fully practical biplane glider. Their greatinnovation was that their glider could have been balanced and controlled in every direction, bycombining the actions of warping (twisting) the

wings and turning the rudder for lateral control, andby using a device called an elevator for up anddown movements without any need for the pilot toswing his torso and legs in order to control the flightdirection. All flight control today has developed fromthis 1902 Wright glider.The development of the airplane is a twentieth-century phenomenon. From the first poweredaircraft to the creation of the supersonic transport,airplanes improved quickly. This was aided by theinnovations of World War I and World War II.Demand for air travel led to the creation of anindustry including aircraft construction companies,engine and equipment makers, as well as firms thatbuilt and operated airports.AtomThe first person to propose that matter was made of atoms,and then write it down, was a Greek philosopher namedDemocritus. The Greek concept of the atom was unlike ours:to their minds a pickle was composed of small green souratoms, a fire of hot light bright atoms, etc.A number of scientists, starting probably with Newton in thelate 1600s, proposed a corpuscular, or atomic, model. But itwasn'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 hadbeen done on gases, and to calculate atomic weights ofelements. In addition to Dalton's work suggesting the atom


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because of fixed chemical combining rules, there was theastoundingly successful kinetic theory of gases, a subject ofintense interest in the nineteenth century, which relies utterlyon gases being made of little bits of flying matter.However, Dalton did not prove that atoms existed...he justshowed that the concept of atoms was useful and helpedexplain 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 showthat when thin gold foil is bombarded by helium nuclei (alphaparticles), the particles are occasionally deflected by a verylarge angle, but usually pass straight through. This gave riseto the realization that the gold was composed of atoms, with atiny nucleus at the middle, which could occasionally collidewith an alpha particle and send it flying.LaserA laser is a device that creates and amplifies anarrow, intense beam of coherent light.The word laser is an acronym for light amplificationby 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. Atomsradiate light in random directions at random times.The result is incoherent light -- a technical term forwhat you would consider a jumble of photons goingin all directions.The trick in generating coherent light -- of a singleor just a few frequencies going in one precisedirection -- is to find the right atoms with the rightinternal storage mechanisms and create anenvironment in which they can all cooperate -- togive 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 Einsteindescribed the theory of stimulated emission.However, it was not until the late 1940s thatengineers began to utilize this principle for practicalpurposes. At the onset of the 1950's severaldifferent engineers were working towards theharnessing of energy using the principal ofstimulated emission. Notable amongst them were:Charles T ownes at the University of Columbia;Joseph Weber at the University of Maryland andAlexander Prokhorov and Nikolai G Basov at theLebedev Laboratories in Moscow. These engineerswere working towards the creation of what wastermed a MASER (Microwave Amplification by theStimulated Emission of Radiation), a device thatamplified microwaves as opposed to light and soon found use in microwave communication systems.T ownes and the other engineers believed it to bepossible create an optical maser, a device forcreating powerful beams of light using higherfrequency energy to stimulate what was to becometermed the lasing medium.However Theodore Maiman was the first scientist

who made the first Laser in 1960 using a rubycrystal. But still Both T ownes and Prokhorov wereawarded the Nobel Science Prize in 1964.


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The Laser was a remarkable technical breakthrough,but in its early years it was something of atechnology without a purpose. It was not powerfulenough for use in the beam weapons envisioned bythe military, and its usefulness for transmittinginformation through the atmosphere was severelyhampered by its inability to penetrate clouds and

rain. Almost immediately, though, some began tofind uses for it. Maiman and his colleaguesdeveloped some of the first Laser weapons sightingsystems and other engineers developed powerfullasers for use in surgery and other areas where amoderately powerful, pinpoint source of heat wasneeded. T oday, for example, Lasers are used incorrective eye surgery, providing a precise source ofheat for cutting tissue.VaccinationVaccination is a term coined by Edward Jenner, anEnglish country doctor, for the process ofadministering live, albeit weakened, microbes to

patients, with the intent of conferring immunityagainst 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 naturalsurroundings since childhood. He had always beenfascinated by the rural old wives tale that milkmaidscould not get smallpox. He believed that there wasa connection between the fact that milkmaids onlygot a weak version of smallpox, the non-lifethreatening cowpox, but did not get smallpox itself.A milkmaid who caught cowpox got blisters on herhands and Jenner concluded that it must be the pus

in the blisters that somehow protected themilkmaids.In 1796, Jenner decided to try out a theory he haddeveloped. A young boy called James Phipps wouldbe his guinea pig. He took some pus from cowpoxblisters found on the hand of a milkmaid calledSarah. She had milked a cow called Blossom andhad developed the tell-tale blisters. Jenner injectedsome of the pus into James. This process herepeated over a number of days graduallyincreasing 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 fullrecovery with no side effects. It seemed that Jennerhad made a brilliant discovery.Jenner encountered the prejudices andconservatism of the English society at that time.People could not accept that a country doctor hadmade such an important discovery and Jenner waspublicly humiliated when he publisized his findings. However, eventually his discovery had to beaccepted a discovery that was to change theworld. So successful was Jenner's discovery, that in1840 the government of the day banned any othertreatment for smallpox other than Jenner's. Jenner

did not patent his discovery as it would have madethe vaccination more expensive and out of thereach of many. It was his gift to the world.Clocks and watches


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Clocks, whether on the wall, or computers, or on ourwrists in the form of watches, are the standardmethod for measuring time. The concept of timedates back to the ancient times. The prehistoricman began

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