Science Projects And Inventions

"Chewing gum! A new and superior preparation of Spruce Gum." Chicago Daily Democrat, October 25, 1850 Chewing gum is widely regarded as an American phenomenon, but the practice of chewing a form of gum actually dates back to prehistory and Europe. Thousands of years later the ancient Greeks were chewing mastiche, a resin from the mastic tree, and the ancient Mayans were chewing chicle, a rubbery sap from the sapodilla tree. Native Americans chewed a gum made from the resin of spruce trees, and it was from this that-the American John Curtis invented his chewing gum. In 1848 he sold his "spruce gum" commercially, which started a fashion for the chewy substance. Gradually spruce gum was replaced by gum made from paraffin wax, which was then sweetened and sold by Curtis around 1848. Modern chewing gum came into being rather by accident. The Mexican general Antonio Lopez de Santa Anna more...

"[No one has] affected the current good or the future welfare of mankind as much as Kary Mullis." Ted Koppel, on ABC's "Nightline" Kary Mullis (b. 1944) was working at Cetus Corporation in Emeryville, California, in 1985 when he worked out a way to duplicate a single piece of DNA into as many copies as were wanted. The technology that resulted from his idea was named polymerase chain reaction, or PCR. The technique could be done in a test tube with the aid of enzymes and temperature changes. After overcoming initial challenges in the laboratory, PCR took off as a huge technological advance in the study of molecular biology. Previously, 5,000 papers had been published on the subject. Not only did the technology provide scientists with a seemingly unlimited amount of DNA derived from something as small as a single strand, it also sped up the process by which they more...

"The challenge is to make toys that allow kids to create, experiment, and explore." Mitchel Resnick, MIT Media Lab Ole Kirk Christiansen was a humble carpenter from the small Danish town of Billund when he began making wooden toys for children in 1932. With Europe still in the grip of a depression and work as a carpenter hard to find, Christiansen's finely crafted toys proved hugely popular. In 1934 he formed his own company and named it Lego, a contraction of the Danish phrase leg godt, meaning "play well." In 1947 the company bought Denmark's- first plastic injection-molcfing machine and began to focus on plastic toys. By 1951 plastic toys made up half of the company's sales, although it was another eleven years until Ole, working with his son Godtfred, created the plastic blocks that became officially known as LEGO". Christiansen had first made plastic interlocking blocks in 1949. These more...

Nothing brings a community together like the collective glow of its televisions. In the spring of 1948, American  John  Walson  (1914-1993)  installed community antenna television, bringing the wonders of cable television to his customers. Walson and his wife Margaret, owners of the Service Electric Company of Mahanoy City, Pennsylvania, came up with cable television as a way to help their customers pick up signals blocked by nearby mountains. Walson decided to take his service literally to new heights by climbing to the top of a mountain and planting an antenna. Using cables and signal boosters, he connected the antenna to his appliance store. Along the way he dropped the signal directly off at his customers' homes, thus creating the first community antenna television system. Community antenna television, now known as Cable TV, is found in nearly 60 percent of U.S. homes and throughout Europe. The first cable systems consisted of more...

"Things are seldom what they seem /Skim milk masquerades as cream." Sir William Schwenck Gilbert, H.M.S. Pinafore Russian doctor Osip Krichevsky first produced powdered milk in 1802. It is made by drying or dehydrating milk until it forms a fine white powder. This can be achieved either by spraying a fine mist of milk into a heated chamber or by adding the milk in a thin layer to a heated surface, from which the dried milk solids can be scraped off. Freeze-drying is now used because it conserves more nutrients and the milk can be fortified to improve its nutritional value. The resulting powder can then be stored for long periods, because the dry environment means it is less prone to bacterial contamination that would spoil fresh milk. As well as its potential for long-term storage, powdered milk has several practical advantages over fresh milk. In the developing world, its more...

"Those who admire modem civilization usually identify it with the steam engine..." George Bernard Shaw, playwright and writer Thomas Newcomen (1663-1729), a Devonshire blacksmith, developed the first successful steam engine in the world and used it to pump water from mines. His engine was a development of the thermic syphon built by Thomas Savery, whose surface condensation patents blocked his own designs. Newcomen's engine allowed steam to condense inside a water-cooled cylinder, the vacuum produced by this condensation being used to draw down a tightly fitting piston that was connected by chains to one end of a huge, wooden, centrally pivoted beam. The other end of the beam was attached by chains to a pump at the bottom of the mine. The whole system was run safely at near atmospheric pressure, the weight of the atmosphere being used to depress the piston into the evacuated cylinder. Newcomen's first atmospheric steam more...

How often have you been listening to your favorite radio station in your car, only to have it slowly dwindle away as you drive out of range of the transmitter? The answer to this problem came in 2001 when a new way to receive radio made its debut—a national service beamed from outer space that, in return for a  subscription fee, offered 100 different channels, none of which would be interrupted by poor reception. The coverage, provided by two or three high-orbit satellites, came as a strong signal requiring no satellite dish, just an antenna the size of a matchbox. Although the broadcast could be dampened by skyscrapers or long tunnels, the signal was bolstered by transmissions from ground-based towers. Two companies were originally granted licenses to provide satellite radio in 1997: XM and Sirius, with XM getting off the mark first in the U.S. in September 2001 and Sirius more...

"The longer we were in it, the smaller it seemed to get..." William Beebe, deep-sea explorer Otis Barton's (1899-1992) famous marine exploration vehicle was reminiscent of a naval mine. A simple sphere made of steel, it once dangled from a 2-mile (3.5 km) cable deep into the ocean. Unlike a mine, however, the bathysphere was intended to hold two intrepid explorers, and at less than 5 feet (1.5 m) across, it was not exactly designed for comfort. In 1928, Barton was just a student, but his blueprint for the bathysphere caught the attention of scientist and explorer William Beebe (1877-1962). A collector of rare species, Beebe had already consulted several professional engineers about building a deep-sea diving vessel. He was impressed by Barton's design and started making plans for a test dive. The secret to the bathysphere's success was its simplicity—its spherical form meant that pressure was evenly distributed across more...

"A weak mind is like a microscope, which magnifies trifling things, but cannot receive great ones" Lord Chesterfield, English aristocrat The first microscopes were made around 1590 by the father and son team of Hans and Zacharias Jansen. These   Dutch   spectacle-makers fashioned   a microscope with a magnification of just twenty times. In 1673 Dutch Antony van Leeuwenhoek discovered bacteria (animacules), blood cells, protozoa, and spermatozoa with a microscope that magnified objects by 300 times. By 1886 Ernst Abbe had advanced the technique quite considerably, and his microscope reached the limits of resolution with visible light— about 2,000 angstroms, or 0.0002 millimeters. But to get better resolution you need something with a smaller wavelength. Ernst Ruska (1906-1988) and his professor, Max Knoll (1897-1969), realized that if electrons were accelerated in a vacuum, their wavelength could be one hundred thousandths that of visible light. These electron beams could then more...

A monorail replaces the more usual two-rail transport system with a single track, and its vehicles either straddle the rail or hang from it. In the first type, the pillars supporting the rail can be of different heights, and so rough terrain can be crossed cheaply. In the second type the rail can be suspended above canals and rivers, taking up little valuable land. In June 1825 Henry Robinson Palmer (1795-1844) opened a suspended monorail in Cheshunt, near London. Although designed to carry bricks, it could also carry passengers. For the United States Centennial Exposition of 1876, General Le-Roy Stone built a demonstration pillar monorail in Philadelphia. Other pillar monorail systems were built to carry agricultural products and mineral ores. The most famous passenger-carrying pillar monorail was the Irish 9-mile (14.5 km) Listowel and Ballybunion railway that ran from 1888 to 1924. A German suspended monorail in Wuppertal started service more...