Science Projects And Inventions

"The world has become uglier since it began to look into a mirror-everyday." Karl Kraus, journalist, poet, and playwright Primitive peoples would have found their reflections in the surface of still ponds, while mirrors used in early Greek and Roman civilizations and in Europe during the Middle Ages were highly polished pieces of metal that reflected light off their surfaces. However, the real leap forward for vanity occurred during the early sixteenth century, when the Venetians developed a method of backing a plate of flat glass with a thin layer of reflecting metal that was an amalgam of tin and mercury, much increasing the clarity of the reflection. The earliest mirrors were hand mirrors used for personal grooming, and later as objects of household decoration with frames made of ivory, silver, or carved wood. The chemical process of coating a glass surface with metallic silver, from which modern techniques of more...

“Archimedes has states that given the force, any given might be moved… Plutarch, Life Marcells The extent to which human beings extend their natural capabilities through the use of machines is something that distinguishes us from other members of the animal kingdom. Cranes are an especially relevant example of this; the ability to raise and maneuver weights vastly greater than those that people could lift and move unaided has played a defining role in the development of human society. The crane is a system of pulleys and cords or wires attached to a framework that enables the movement of heavy weights both vertically and horizontally through the use of mechanical advantage. The earliest cranes have been dated to approximately 550 B.C.E., although there are Greek architectural constructions still in existence that predate this by several hundred years, and that undoubtedly would have required some sort of supporting pulley mechanism. Cranes more...

"The use of radar in World War II... was a vital factor in the successful defense of Great Britain" R. Hanbury Brown, Robert Watson-Watt, physicists In 1935, with hostilities looming in Europe, the British government asked Scottish physicist Robert Watson- Watt (1892-1973) to develop a personnel-destroying "death ray" that could harm the opposition. Watson- Watt demonstrated that this was an impossible ambition. However, he theorized that a radio wave could be sent to bounce against a moving object, and monitoring its travel could then provide information about the target, such as its speed, direction of travel, and altitude. This could also determine the distance from the transmitter of fixed objects. A demonstration won favor with the government, and Watson-Watt subsequently gave the technology the name radar (radio detection and ranging). By the beginning of World War II, Watson-Watt had installed a chain of radar stations across the United Kingdom, and more...

"Obedience... /Makes slaves of men, and, of the human frame/ A mechanized automaton." Percy Bysshe Shelley, "Queen Mab" (1813) Most people think of self-operating machines as twentieth-century inventions. Although Isaac Asimov coined the word "robotics" in 1942, and Grey Walter built the first electronic autonomous robots in 1948, the first automaton for which we have good evidence was a boat with four mechanical musicians. It was built more than eight hundred years ago by Islamic scholar AI-Jazari (1150-1220). AI-Jazari, considered by some to be the father of robotics, wrote his Kitab fima'rifatal-hiyalal-handasiyya (Book of Knowledge of Ingenious Mechanical Devices) in about 1206, while he was the palace chief engineer in Diyarbakir (located in the southeast of present-day Turkey). The book describes a boat he constructed that floated on the palace lake and entertained guests at parties with music from a flute, a harp, and two drums played by automatons. The more...

When repeater rifles came into their own in the mid- 1800s, warfare changed forever. Single-shot rifles had long been predominant; the repeater, however, had a magazine holding several rounds of ammunition, so continual reloading was not necessary. Repeater models had been around since the seventeenth century, but they required separated-out ammunition elements rather than all-in-one metallic cartridges. In 1860, New Hampshire-born gunsmith Benjamin Tyier Henry (1821-1898) patented a repeater that used a lever action to load its .44 caliber rimfire metallic cartridges—often seen as the first truly self- contained cartridges. It produced continuous fire that was much faster than that of the prevailing muzzle-loading musket, giving one man the firing power of several. The "Henry" had its shortcomings but was very popular with soldiers during the American Civil War, as was Christopher Spencer's slightly different repeater, which appeared at the same time as Henry's. By the time Henry produced his more...

"Scissors... evolved, step by step, [with] many other tools destined to cut, separate, and pierce." Massimiliano Mandel, Scissors Spring-type scissors probably date from the Bronze Age. Consisting of blades connected by a C-shaped spring at the handle end, they were used in Egypt from 1500 B.C.E. to cut silhouettes for artwork. Pivoted scissors used in ancient Rome and parts of Asia were made of bronze and iron, as were sixteenth- century European ones. Scissors and other implements became more widely used as their quality improved with better methods of metal forging, but cast steel was not used until 1761, when Robert Hinchliffe manufactured scissors in Sheffield. Many were hand- forged with elaborate handles, but the styles were simplified in the nineteenth century to facilitate large-scale mechanical production. The steel used in scissors contains varying amounts of carbon, depending on the quality of scissors. Drop hammers form the rough shape of more...

"With this apparatus regularly and daily used, the teeth and gums will be preserved free from disease." Levi Spear Parmly Appalled by the terrible condition of his patients' teeth, U.S. dentist Levi Spear Parmly (1790-1859) was spurred into promoting the use of what is now called dental floss. He encouraged people to clean between their teeth using a thin piece of waxen silk thread, and even went so far as to state that flossing combined with the use of a toothbrush and dentrifice would eliminate bacteria from the gums. While this might have been a slight exaggeration, the use of dental floss is today widely recognized as one of the most important, and least utilized, forms of oral hygiene. The practice of cleaning between the teeth with thread or small picks is one that predates Spear Parmly, but he reinvented the procedure and the tools to do it, and publicized more...

In 1969, while everyone else was experimenting with LSD, Gary Starkweather was hard at work at Xerox's research facility in Webster, New York, experimenting with the laser printer. Two years later, Starkweather, who has since won an Academy Award for his work with Pixar on film input scanning, constructed the first working laser printer system. The laser printer relies on the concept that—like magnets—opposites attract. The laser printing process begins with the laser applying the desired pattern on the revolving printer drum. The beam reverses the drum's positive charge, making certain areas negatively charged. These negatively charged areas attract toner, a positively charged powder. After a wire applies a strong negative charge to the printing paper, a rolling belt feeds the paper past the drum. The toner is pulled from the drum by the paper. The paper is then zapped to neutralize its charge.  I Before the paper can be more...

In 1948 New Zealander Richard Barrer (1910-1996) was the first to manufacture a type of zeolite that had not been found in nature. He became the professor of physical chemistry at Imperial College, London. Natural zeolites are a form of microporous stone that have such a regular and tiny pore structure that they can be used as molecular sieves. Up to 50 percent of the volume of the stone is open space, or air. Zeolites are produced when layers of fine volcanic ash react with alkaline water; the mineral natrolite is a typical example. Open-cast mines yield about 4 million tons of zeolites per year and these are mainly used in the concrete industry. In agriculture zeolites can be added to soil to act as a water trap. The zeolite is hygroscopic and can abstirb up to half its own mass of water from the morning dew, only to release more...

Lasers (standing for Light Amplification by Stimulated Emission of Radiation) are now part of everyday life. They form a key component of CD and DVD players and the scanners used at supermarket checkouts. Their ability to direct energy with pinpoint precision give them a wide spectrum of uses as dental drills,metal cutters, welders, and scalpels for eye surgery. The laser process- begins with a population of atoms that has, been optically pumped so that there are more atoms at a higher energy level than at a lower level. Decay then produces photons of light that stimulate the emission of other decays and so a cascade of photons is produced. The lasing substance is contained in a resonant cavity that has mirrors at each end. Photons travel back and forth between the two mirrors stimulating feedback and the system "lases" if the gain due to stimulated emission exceeds the losses due more...