Science Projects And Inventions

"The telephone is a good way to talk to people without having to offer them a drink." Fran Lebowitz, writer Superheroes may use phone booths to change into spandex, prostitutes may use them to place calling cards, and hooligans occasionally abuse them as urinals, but the impetus for the first payphone initially sprang out of an individual's desperate need for the use of a telephone and not being able to find one. Conscious of this need, U.S. inventor William Gray devised the first coin-operated pay phone in 1889. It was a post-pay machine so the money was paid after the call to an attendant. Demand for .the device was not immediate, but he managed to interest telephone companies, hotels, and shops. As people traveled more, the need for public payphones grew, and Gray's idea fueled the demand for household telephones. Phone booths have undergone more design changes over the years more...

“[I was] ...the instrument destined to take away from the world one of its greatest calamities..." Edward Jenner, scientist and doctor As Edward Jenner (1749-1823) was growing up in England, smallpox had again become prevalent and was ravaging London and the countryside. Jenner became a doctor, practicing in Gloucestershire where he became interested in the link between cowpox and smallpox. Milkmaids who contracted the non- deadly cowpox seemed immune to smallpox, and Jenner, intrigued by this, began to investigate the link. In May 1796, milkmaid Sarah Nelmes contracted cowpox from her cow, and pus-filled blisters covered her hands and arms. She visited Dr. Jenner. Realizing his opportunity to test the protective properties of cowpox on someone who had not contracted smallpox, Jenner took some pus from Sarah and applied it to scratches made on the arm of a young boy, James Phipps. Some days later Phipps came down with a more...

The development of pastes designed to clean teeth and freshen the breath began in Egypt as early as 5000 B.C.E. Myrrh, volcanic pumice, and the burned ashes of ox hooves were mixed with crushed eggshells, oyster shells, and other fine abrasives, then applied with a finger to scour teeth and help remove food and bacterial deposits. In China around 300 B.C.E. a nobleman named Huang-Ti claimed that toothaches could be cured by inserting pins into certain areas of a patient's gums. Huang-Ti's theories grew to become the world's first recorded and systematic approach to oral hygiene. Generally, however, the composition of what people used as toothpaste remained an intriguing mix of practicality, myth, and superstition until well into the seventeenth century. In the first century C.E., for example, it was thought that toothaches could be avoided by removing animal bones from wolves' excrement and wearing them in a band around more...

Odds are that if you check your purse or wallet right now, you'll find an invention that owes its existence as much to a desire for neatly pressed clothes as a need for portable data storage—the magnetic stripe card. Conceived by IBM engineer, Forrest Parry, as part of a government security system project, the technique of attaching a strip, or "stripe," of magnetic tape to a card facilitated a revolution in portable, personal data retrieval. Until the advent of the chip-based smart card during the 1980s, the magstripe ruled—from club membership cards, through to phone, credit, and debit bankcards. Parry had experienced several frustrating failures with trying to fix the magnetic material to the card with adhesive. When a forlorn-looking Parry returned home from the laboratory, his wife, who was ironing at the time, stepped in and suggested she try using the heat of the iron to bond the magstripe more...

The electrocardiograph—also known as EKG or ECG— is an instrument designed to record minute electric currents generated within the heart, which are used to diagnose different types of heart disease. At the end of the nineteenth century, physiologists understood that beating hearts produced electrical currents, but they could only measure them by placing electrodes directly on heart muscle. Dutch physician and physiologist Willem Einthoven (1860-1927) adapted the string galvanometer for use in cardiology. String galvanometers had first been used to amplify electrical signals transmitted along undersea cables. Einthoven's galvanometer, which he produced in 1903, consisted of a microscopic thread of quartz known as a "string" that was vertically suspended in a strong magnetic field. When minute currents passed through the string it deflected and obstructed a beam of light, allowing the shadow to be recorded on photographic paper. Early prototypes were unwieldy—weighing 600 pounds (272 kg), they needed to be more...

"I was obliged to rise up every few minutes to see that I sailed in the right direction." Sergeant Ezra Lee, pilot of Turtle In 1775 Britain's North American colonies rebelled against British rule, precipitating a War of Independence. An enthusiastic American patriot, David Bushnell (1742-1824) of Saybrook, Connecticut, devised a secret weapon to counter the might of Britain's Royal Navy. He designed and built a submersible vessel to attack warships in harbor. Bushnell's Turtle was an oval-shaped vessel of wood and brass, just large enough to hold one person. It had ballast water tanks that were filled to make it dive, then emptied with a hand pump to return to the surface. Two screw propellers, operated by foot pedals and a handle, allowed the operative to maneuver the vessel laterally and vertically underwater. Ingeniously, the inside of the submersible was lined with naturally luminescent wood to provide light for more...

"The inspiration for the optical disk was an illustration in a technical news magazine..." David Paul Gregg The DVD disk has its roots way back in 1958 when engineer David Paul Gregg, while working for the U.S. Westrex corporation, had the inspiration to create a new format for audio and video. He had seen an article that showed the results from an early scanning electron microscope, which had lines drawn by the electron beam that were less than a tenth of a micrometer wide. Gregg imagined a plastic disk with tracks written on it that could be read with an inexpensive optical reader—the equivalent of a stylus reading the tracks on a traditional vinyl LP. Gregg's original concept, which he patented in 1961, was of a transparent disk, through which a concentrated beam of light would be shone and picked up on the other side by a reader. Like an more...

"The sand had etched the glass... and revealed the contrast against parts... covered by steel mesh" H. J. Plaster, A Tribute to Benjamin Chew Tilghman Legend has it that Benjamin Chew Tilghman (1821-1901), when based in the desert with the U.S. Army, noticed the effect that windblown sand had on the windows of the army buildings, and developed his ideas on sandblasting from there. Tilghman proposed that grains of sand, or quartz, fired at high speed toward a hard surface would allow smoothing, shaping, cleaning, and engraving with greater accuracy and power than current methods. Using compressed air, steam, or water to propel the grains, Tilghman was able to etch away at the surface of a substance harder than the grains themselves. Stone engraving was not new but Tilghman's system replaced the expensive and time- consuming process of hand-chiseling, allowing the user to create effects on any hard surface. From more...

An early incandescent light bulb with the coils giving electrical contact to the filament inside the glass. Decades before Thomas Edison filed a patent for his electric lamp, Scotsman James Bowman Lindsay (1799-1862) produced constant electric light in what became a prototype of the modern light bulb. Building on Humphry Davy's successful yet impractical platinum incandescent light, which he developed in 1802, Lindsay managed to create a more usable form of the light bulb. Having secured a position as a lecturer at the Watt Institution in Dundee, Scotland, in 1829, Lindsay began experimenting with constant electric light. He demonstrated his invention in 1835 at a public meeting in Dundee. The light from an incandescent bulb is produced from a filament through which an electrical current is passed. Lindsay claimed that, with his light, he could "read a book at a distance of one and a half foot." This was an more...

"The English are fools... they give their children the smallpox to prevent their catching it." Voltaire, Letters on the English (c. 1778) Smallpox is believed to have first appeared around 10,000 B.C.E. Ramses V died suddenly in 1157 B.C.E.; his mummy bears scars that have a striking resemblance to those left by that scourge. Smallpox killed about a third of its victims and left many survivors scarred. But it was noted that survivors never got smallpox again. After the eldest son of China's Prime Minister Wang Dan died around 1000 B.C.E. of smallpox, Wang Dan sought a cure for it. A Daoist monk introduced the technique of variolation, a type of inoculation. Scab- coated pustules taken from survivors were ground up and blown into the nose like snuff. Reports of inoculation reached Europe in the 1700s. In London, in 1721, Lady Wortley Montague and the Princess of Wales urged that more...