Science Projects And Inventions

"Man lives by images. They lean at us from the world's wall, and Time's." Robert Penn Warren, poet Computer scanners (or "optical scanners") take images and turn them into signals that a computer can understand. Although image scanners did exist prior to the invention of the charge-coupled device (CCD), most modern scanners now capture images in this way. A scanner houses an array of CCDs for capturing light. When a photograph or book is scanned, a lamp illuminates the image, which is then reflected by a series of mirrors and focused through a lens to reach the CCD array. The CCDs create an analog signal, which is then converted to a digital signal that can be read by a computer and stored. More recently, manufacturers have started to use a different technology—the contact image sensor (CIS) method, which reflects light from LEDs (light-emitting diodes), instead of from a normal lamp, more...

"Good fortune is what happens when opportunity meets with planning." Thomas Alva Edison The idea behind the stock ticker, which derived originally from telegraph technology, was to provide stock prices via a telegraph machine. It earned the name "ticker" because of the noise it made as prices came through, which also explains the name "tick" for the up or down movement in the price of a security. E. A. Calahan of the American Telegraph Company invented the first stock ticker in 1867. Others came on the market shortly afterward, but it was not until Thomas Alva Edison (1847-1931) created the Universal Stock Ticker for Gold and Stock in 1871 that the machine's efficiency was greatly improved. Edison created the "screw-thread unison" device that enabled stock tickers to be synchronized, allowing them to transmit the same information at the same time. This was a huge improvement on previous models, which had more...

“I always had the idea that a catheter shouldn't be used more than one time." David Sheridan Half a century ago, urinary catheters were made of laminated, braided cotton. Rather than being disposable, they were cleaned and reused. Far more than just turning the stomachs of the patients who needed them, the catheters posed an increased risk of infection—with potentially fatal consequences. That all changed with the dream of David Sheridan (1908-2004). While working as a floor refinisher, this American son of Russian immigrants decided that he could make a better catheter. That dream, coupled with the fact that World War II threatened to cut off U.S. hospitals from their French catheter suppliers, caused Sheridan to act. Despite having only an eighth-grade education, Sheridan invented a machine that allowed hollow rubber tubes to be made into catheters that could be used a single time, and then discarded. A painted strip more...

Most people are aware of the usefulness of Bubble Wrap" for packaging china, glass, and other precious items to prevent them from breaking. However, what is not quite so well-known is that this versatile polythene packaging was originally intended as a unique type of wall decoration. In 1957, U.S. engineer Alfred Fielding and Swiss inventor Marc Chavannes were trying to produce a textured plastic wallpaper that would be easy to clean. Their early designs did not work, but thinking quickly they transformed their accidental product into a new kind of packaging. On the basis of this new invention, they then founded Sealed Air, a global corporation that now turns over $4 billion a year. Not bad for an invention based on thin air. Sealed Air's Bubble Wrap® is superior to other cellular polythene packaging because it has a barrier layer giving extra protection. During the manufacturing process, a sheet of more...

In the early 1860s, French microbiologist and chemist Louis Pasteur (1822-1895) showed what a few scientists had already begun to suspect—that the rotting of organic tissue (gangrene) was caused by bacteria rather than by chemicals in the air (or "miasma"), as had been previously thought. After reading a paper by Pasteur, English surgeon Joseph Lister (1827-1912) set about conducting his own experiments. Reaching the same conclusion as Pasteur, Lister then sought a way to get rid of the microorganisms that caused gangrene by applying a chemical solution to wounds. Carbolic acid, or phenol, had been used for deodorizing sewage, so Lister applied a solution of carbolic acid to both surgical instruments and open wounds. He found that by doing so the incidence of gangrene In patients in his care was vastly reduced. He had created the first antiseptic to be used in medical practice. In 1867 Lister outlined his findings more...

Photolithography is a modern development of an older process used in printing. In lithography, smooth pieces of limestone had oil-based images burned by acid into their surface. The non-oily portions were then sealed by gum arabic. Oil-based ink then only adhered to the unsealed areas so that complicated pictures and typed regions could be reproduced. Photolithography is used in the mass production of transistors and electronic components. In April 1957 Jay Lathrop and James Nail of the U.S. Army's Diamond Ordnance Fuse Laboratories in Maryland produced the first electronic components that did not require manual soldering. The required design is often pre- formed on a photo-mask, consisting of a series of opaque chromium lines on glass. The aim of the process is to transfer the pattern of the mask onto the flat surface of a wafer of silicon. The silicon is cleaned and covered with a photo-resistant substance. Ultraviolet light more...

"Some people change their ways when they see the light, others when they feel the heat." Caroline Schroeder, pianist The bimetallic bar was invented by the Yorkshire clockmaker John Harrison (1693-1776), and was used in his third and fifth chronometers to cancel out thermally induced variations in the balance springs. Imagine two straight strips of metal bar—steel and brass, say—riveted, brazed, or welded together along their length. Brass expands by nineteen parts in a million for every increase in temperature of 1.8°F (1°C), and steel by thirteen parts. Heating the bar will make one metal expand more than the other and cause the bar to bend. In the above example, the brass will be on the outer side of the curve. Cooling the bar will cause it to curve the other way, with the steel on the outside. A spiral bimetallic strip unwinds or tightens as a function of temperature; more...

Trawling is a type of fishing in which one or mote boats (trawlers) pull a fishing net through the water behind them. This can involve dragging the net along the sea floor (known as bottom trawling) or pulling it along higher in the water (pelagic trawling). It is impossible to say when this method was first used in its simplest form, but there is evidence of concerns about its environmental impact as early as the fourteenth century, when fishermen protested against bottom trawling because of the indiscriminate way in which it caught all types and sizes of fish. It was not until the late eighteenth century that modern beam trawling, a method of bottom trawling where the mouth of the net is held open by a solid metal beam, was widely used. The fishermen of both Barking and Brixham in England claimed credit for pioneering this technique, and it led more...

"When you see the little green pictures on CNN of people ...at night, think of Professor Spicer." Piero Pianetta In early World War II, U.S. engineer William Spicer (1929-2004) was aware of the visibility problem of conducting military operations at night and was looking into a solution based on photoemission. In photoemission, light is treated as packages of energy called photons, which strike a material to bounce out electrons. In 1942 Spicer developed the first night vision goggles using image enhancement. At night, light is present in small quantities from various sources, but our eyes may not detect it. The photons from this light enter the goggle lens and strike a light-sensitive surface called a photocathode, releasing electrons. The electrons are accelerated toward a microchannel plate that releases thousands more electrons through a cascade reaction. These electrons hit a screen coated with phosphor chemicals to emit visible light. As thousands more...

The 1968 Kail Joint Computer Conference at San Francisco in the United States presented a remarkable number of "firsts." Among them was the first video teleconference; the first use of hypertext (the foundation of today's web links); and the first presentation, by the Stanford Research Institute (SRI), of NLS, short for oNLine System, the revolutionary ancestor of modern computer server software. Such dazzling displays likely distracted people from another important first, moved by the hand of SRI researcher Douglas Engelbart (b. 1925): the computer mouse. Far from the sleek ergonomic devices of today, the first computer mouse was a wooden box with wheels and a thick electric cord. Engelbart and colleague Bill English (b. 1929) first came up with the idea in 1963, and created the device as a very small piece of a much larger computer project. They were looking for something that allowed computer users to easily interact more...