10th Class

Thanks to some unknown inventor, self-heating cans first appeared around 1900 for use by mountaineers and explorers. The most common versions involve a can with two chambers—one for the food and one for the heating unit. The heat is generated by an exothermic (heat-producing) chemical reaction between calcium oxide (quicklime) and water. The heating unit is contained in either an outer chamber surrounding the food, or an inner compartment immersed in the food or drink. It is activated by pressing a button or poking holes to break the seal between the water and quicklime. The reaction heats up within a few seconds, and heats the food inside the can in minutes. During World War II, Heinz manufactured self- heating beverages with a cordite stick down the center that heated the contents when lit, but they were not always reliable. Legend has it that the first recorded casualty of the D-day more...

"Spring hasn't really arrived until you are awakened by the first lawn mower." Source unknown To some it is the one of the most annoying sounds made by machines, while to others it has an almost musical quality. We are talking, of course, about the buzzing noise of the two-stroke engine. From motorbikes to lawn mowers this invention has been the model of simplicity in the world of internal combustion, and its modern design originated with British engineer Joseph Day (1855-1946). An earlier two-stroke engine had been devised by Dugald Clark in 1880, but it lacked the simplicity of Day's version. Using just three moving parts, Day's engine used the pressure below the piston to force the fuel and air into the combustion chamber while simultaneously pushing the exhaust gases out. This meant that a pulse of power could be sent along the drive shaft with every revolution—an efficiency improvement more...

“I put some tempera water-based paint in a bottle and took my watercolor brush to the office..." Bette Graham The correction fluid used worldwide to cover mistakes on paper began life in the United States in a single mother's North Dallas kitchen. In 1951, Bette Graham (1924-1980) was a young divorcee bringing up a small son, Michael (later Mike Nesmith of the Monkees pop group) and working as a secretary at Texas Bank & Trust. Bette and her colleagues appreciated the new speedy electric typewriters, but their carbon-film ribbons made fixing mistakes messy. The only answer was to type the whole sheet again. Bette harbored artistic ambitions that had been thwarted by an early marriage. The story goes that her artist's eye spotted workers who were decorating the bank's windows and covering mistakes with an extra paint layer. Soon Bette was doing the same with a pale water-based tempera paint. more...

"Success is more a function of consistent common sense than it is of genius." An Wang Nowadays we trust computers to store more and more of our important records and information. However, before the 1950s no one would have even considered trusting a computer to store data—there simply was not the technology for long-term storage. The first computers were not reliable because they stored data using such means as acoustic waves in mercury-filled tubes or complicated circuits of vacuum tubes. Then, in 1949, a new way of storing binary data was invented: "magnetic core memory." Computers store data as binary information, where each bit of data is stored as a zero or a one (off or on). With core memory, metal cores are magnetized in one of two directions, and this determines whether they store a zero or a one. These cores are threaded together by wire in a flat more...

It is estimated that over 100,000 patents went into the creation of the first practical automobile. At the end of the nineteenth century, the steam car had evolved considerably and was being sold commercially in the United States and the United Kingdom. But manufacturers were still using a lever device, called the steering tiller, to direct the vehicle, which made steering motor cars difficult and strenuous. Alexander Winton (1860-1932), a keen cyclist and owner of Winton Automobiles, had been trying to replace the tiller on his car with a system modeled on a bicycle's steering. He came up with a circular wheel with a tube running down to a steering box linked to all four wheels. The mechanism in the steering box translated rotation of the wheel into linear action, and gave drivers increased control of their vehicles. Even Henry Ford, inventor and founder of the Ford Motor Company, was more...

Steam engines have been around since the mid- seventeenth century. Noisy monsters, they used steam pressure to push pistons and turn engines, but they were massively inefficient and expensive to run. Engineers and inventors were aware that their machines made inefficient use of steam, and were looking for a better system to harness all that energy. In 1884 British engineer Charles Parsons (1854-1931), head of the electrical section of a ship manufacturer, patented the first steam turbine, which he used as the power source for an electrical generator that he had also built. Using incredibly fast jets of steam had been causing inventors problems because they were just too rapid to use. At low pressure, steam jets were still reaching speeds of more than 1,000 miles per hour (1,610 kph), and at high pressure as much as twice that. Spinning a turbine blade at such a speed would rip it more...

"All technology can be used for bad or good. It's up to you how to use it." Vladimir Zworykin, scientist In 1930, the Soviet Russian physicist Leonid Kubetsky (1906-1956) proposed a method to amplify weak photoelectric currents. He exploited the photoelectric effect where the energy of photons is converted into the energy of moving electrons. These electrons can then be accelerated. When these electrons impact a fluorescent plate, several photons are then dislodged, converting the energy back into visible light. The device, a photomutliplier tube, can increase the illumination fifty-fold. Used in series, these tubes can create a cascade of photons, producing gains in excess of 50,000-fold illumination. In the 1930s, Vladimir Zworykin (1889-1982) was working at RCA on what became the first commercially viable television. To overcome the problem of a weak signal, Zworykin employed a similar photomultiplier. It was Zworykin's design, produced in 1936, that became commercially successful, more...

"The Cadillac car will kill no more men if we can help it. We're going to develop a fool-proof device... " Henry M. Leiand, founder Cadillac Automobile Co. Before the invention of the starter motor, the motorist had to indulge in some energetic "cranking" of the engine with a starting handle before it would fire. Sometimes the engine would misfire, Jerking the handle violently and injuring the hapless motorist. Automatic starters had been proposed some years before—a patent for what turned out to be an impractical solution was granted to Clyde J. Coleman in 1903. Research into a practical system was revisited with some urgency when a friend of Cadillac's founder, Henry Leiand, died following an injury sustained when a starting handle, thrown by a backfiring engine, struck him in the face. Cadillac called upon Charles F. Kettering's (1876-1958) company, Dayton Engineering Laboratories (DELCO)—an entity set up specifically to exploit more...

"A pencil and rubber are of more use to thought than a battalion of assistants." Theodor Adorno, philosopher and musicologist Hevea brasiliensis—otherwise known as the "rubber tree"—had been tapped for thousands of years to harvest its saplike extract (latex, the source of natural rubber) long before anyone knew what rubber was. Rubber's chemical composition was finally cracked by British chemist and physicist Michael Faraday (1791-1867) in 1829. Faraday determined natural rubber's basic chemical formula—C5H8—a molecule that was later named "isoprene." Rubber is composed of many isoprene units strung together, forming a polymer—polyisoprene. Attempting to mimic the natural product of Hevea brasiliensis, scientists set out to reproduce polyfeoprene in the laboratory—and met mostly with failure. Fed- up with isoprene, scientists ditched it for butadiene (C4H6), hoping the change would be more successful in yielding a synthetic polymer similar to rubber. Working in St. Petersburg, and using ethanol to make butadiene and more...

"The maximum warmth produced by the two heaters [was] literally sufficient to roast an ox..." The Evening Journal (August 29, 1892) From the eighteenth century, people began to cook with stoves rather than using open fire, which was dirty, dangerous, and inefficient. The first electric stove was a little longer in coming, although exactly who invented it and when is a matter of some debate. Although  the  Carpenter  Electric  Heating Manufacturing Company produced an electric stove in 1891, the first patent for an electric stove was granted to William Hadaway in 1896. Another claim to the invention comes from Thomas Ahearn (1855- 1938), a Canadian businessman and inventor, who set up the Ottawa Electric Company in 1882. Ahearn was reputedly the first person to cook a meal using electricity in 1892. The early electric stove worked by running electricity through a resistance coil; the coil heats up, which in turn more...