Science Projects And Inventions

"[The] question is how to be ready for a new world of reporting and commentary by Internet rules." Christopher Lydon The first decade of the twenty-first century has seen a proliferation in new communications technology. It is now possible to watch a favorite television show on a laptop, read a newspaper on a cell phone, or listen to a radio broadcast on an MP3 player. The evolution of the podcast is one more important development. A podcast is a digital audio or video file, distributed automatically to a subscribed user. That user can then listen to or view the file on a mobile device such as a personal computer, MP3 player, or cell phone. The podcaster first creates a "show"—usually a video or MP3 audio file—and then an RSS (Really Simple Syndication) feed file that points to where the podcast can be found. The receiver uses "aggregator" software to subscribe; more...

"Conditional co-operation is like adulterated cement which does not bind…” Mahatma Gandhi  Joseph Aspdin (1778-1855) invented the first Portland cement, named after the gray Portland stone it resembled, in 1824. However, his cement set too quickly and had poor early strength. Joseph's son William then noticed that when the constituent clay and limestone are burned together to combine the minerals, increased burning temperatures (exceeding 2,282°F/1,250°C) and greater proportions of limestone resulted in much stronger cements suitable for concrete, and hence construction. The difference in strength was largely due to the calcium silicates present. The strength of Joseph's cement was derived from its belite (dicalcium silicate) content, which could take weeks to develop. For early strength, cement has to contain alite (tricalcium silicate), which is precisely what William had produced by using higher burning temperatures. Despite having a different composition than his father's invention, William neither patented his idea nor changed more...

"Much water goeth by the mill that the miller knoweth not of." Proverb In a tidal mill, incoming water enters and fills the millpond through sluices and is then channeled out at low tide to turn the mill wheel, thus powering the millstones, and crushing the grain to flour. The first known tidal mill, dating around 787, was built on Strangford Lough in northern Ireland, and was used by monks to grind corn for the nearby monastery. Tidal mills were used along Europe's Atlantic coast in the Middle Ages, where the high tidal ranges ensured generous payback for the millers. The number of suitable sites was limited, and the mills could only operate for a certain period after each high tide, but their output was predictable compared to weather- dependent windmills and traditional watermills. The popularity of tidal mills waned with the arrival of the steam engine, until in 1966 more...

The forerunner of the modern bristle toothbrush is generally believed to have originated in fifteenth- century China. A Chinese encyclopedia dating to 1498 describes the short, coarse bristles from the neck of a Siberian wild boar being embedded in a handle made from animal bone, which was then used to clean the teeth. In the seventeenth century, Chinese traders took the brush to Europe, where its popularity flourished despite boar hairs being considered too rough for sensitive European gums. Softer horsehair bristles were seen as an alternative, although boar bristles remained the most common fiber. The toothbrush was not humankind's first attempt at dental hygiene. "Toothsticks" dating back to 3000 B.C.E. have been uncovered during excavations of Pharaonic tombs in Egypt. These are lengths of frayed twigs or fibrous wood from shrubs, used to-clean between the teeth and freshen the breath. "Chewing sticks" made from aromatic shrubs for oral hygiene more...

“... it is with great pleasure and satisfaction that we welcome proof of [Lowe's] genius." Professor Joseph Henry, Smithsonian Institution Thaddeus Lowe (1831-1913) did not only invent the humble ice-making machine; he also made waves in aeronautics, engineering, and chemistry. In the course of his work on the cooling properties of compressed gases, he became interested in carbon dioxide specifically and, putting his research into practice, developed the "Compression Ice Machine" in 1865. After the American Civil War, Lowe began extensive research on the properties of gas. Refrigeration is essentially a process whereby heat is removed from an enclosed space and ejected somewhere else. Most systems work by using a chemical, usually gas, to remove the heat. As the gas expands, heat is turned into kinetic energy, cooling the air. In 1869 Lowe and other investors purchased an old steamship equipped with refrigeration units and began shipping fresh fruit and more...

The earliest speech synthesizer was created by a Russian professor, Christian Kratzenstein (1723-1795). Between 1773 and 1779 Kratzenstein made acoustic resonators and produced vowel sounds by connecting them to organ pipes. A contemporary in Vienna, Wolfgang von Kempelen, produced a more advanced machine in 1791. His "acoustic mechanical speech machine" was able to produce single sounds and even words or short phrases. He is best known for an earlier invention, a chess-playing machine named "The Turk." This consisted of a cabinet, housing (apparently) just cogs and wheels, and a manikin with movable arms. One could not see the legless human chess player concealed inside. Once this hoax was exposed, his legitimate speech machine was discredited as well. Alexander Graham Bell became interested in speech synthesis after he saw a replica of one of Von Kempelea's speech machines. When young, Bell had taught his pet terrier to stand between his legs more...

In 1814 German researchers first described the disease "German measles"—later known as rubella from the Latin rubellus meaning "reddish." Rubella is a single- stranded RNA virus spread from person to person via respiratory droplets. It usually causes a mild illness (symptoms include low-grade fever and swollen lyn-iph nodes followed by a generalized rash), but in pregnant women it is an altogether different matter. In fetuses, it can result in congenital rubella syndrome, a condition characterized by deafness, mental retardation, cataracts, heart defects, and diseases of the liver and spleen. Between 1963 and 1964 a rubella epidemic in the United States resulted in 30,000 babies being born with permanent disabilities as a result of exposure to the virus. The tragedy prompted the National Institutes of Health to launch a campaign to find a vaccine. Two pediatricians, Harry Martin Meyer (1928- 2001) and Paul Parkman (b. 1932), isolated the rubella virus and more...

"As a research scientist you are driven by the desire to find things out with ail your might." Gerd Karl Binnig As recently as thirty years ago the idea of being able to "see" bumps and grooves on substances at an atomic scale seemed unachievable. Then, in 1981, Gerd Karl Binnig (b. 1947) and Heinrich Rohrer (b. 1933) created a microscope capable of doing just that. Their scanning tunneling microscope (STM) bears little resemblance to a conventional microscope. Operating at a low temperature and in a vacuum, it consists of a very sharp needle (its end is the width of a single atom), which can be brought very close to the sample being examined. It is a tool that "senses" rather than "sees" because it deals with sizes that are smaller than the wavelength of light. The STM exploits a phenomenon of quantum mechanics known as electron tunneling where electrons more...

"It is... poured around the stone or anything else of this kind that one wishes to fasten." Theophrastus, philosopher and scientist Plaster goes by various names—plaster of Paris, partly dehydrated gypsum, or calcium sulfate hemihydrate. Gypsum is a common mineral found in a variety of crystalline forms, from the fine grain of alabaster to the large, flat blades of selenite. Plaster was first used as a building material and for decoration in the Middle East at least 7,000 years ago. In Egypt, gypsum was burned in open fires, crushed into powder, and mixed with water to create plaster, used as a mortar between the blocks of pyramids and to provide a smooth facing for palaces. In Jericho, a cult arose where human skulls were decorated with plaster and painted to appear lifelike. The Romans brought plasterwork techniques to Europe. Gypsum is found worldwide, as far east as Thailand and as more...

Chemotherapy's effectiveness against cancer was discovered from mustard gas, a lethal weapon used in the World War I trenches. Autopsy observations of soldiers exposed to the gas revealed destruction of lymphatic tissue and bone marrow. Scientists at the time reasoned that mustard gas might destroy cancer cells in lymph nodes, but nothing was done. Early in 1942 Alfred Gilman (1908-1984) and Louis S. Goodman (1906-2000), two pharmacologists at Yale University, were recruited by the U.S. Department of Defense to  investigate  potential  therapeutic applications of nitrogen mustard (a derivative of mustard gas) on lymphoma. After establishing lymphomas in mice and rabbits, they went on to show that they could treat them with mustard agents. The- next step was to inject mustine (the prototype anticancer agent) into a patient with non-Hodgkin's lymphoma, whose cancer had become resistant to radiation. Initially the patient responded well, with doctors noting a softening of the tumor more...