Science Projects And Inventions

The calotype process was created by William Henry Fox Talbot (1800-1877) in the very early days of photography. Athough Talbot was not the originator of photography, his calotype formed the basis of the photographic process for more than 150 years. The calotype, or Talbotype, process will be recognizable to anyone who is familiar with developing photographs. Calotype is derived from the Greek, meaning literally "good impression." Talbot used high-quality writing paper coated with light- sensitive silver chloride. The paper had to be prepared before exposure to light, and then needed ten to fifteen minutes of exposure time in bright light, usually sunlight. The paper was exposed to the light in a wooden box functionally similar to a modern camera. Talbot also realized that short exposure of the light-sensitive paper and then chemical fixing could produce a useful negative. The fixing process removed the light-sensitive silver, making the negative easier to more...

"It has often proved true that the dream of yesterday is the hope of today, and the reality of tomorrow."  Dr. Robert Goddard, American scientist Robert Goddard (1882-1945) gave serious thought to how we might get to the Moon. Despite being met with ridicule, what he gave to rocketry is still being used today. Using mathematics, Goddard worked out the energy-to-weight ratios of various fuels. This showed that gunpowder would never be powerful enough to lift a rocket into space. Also, to burn fuel in a vacuum, a rocket would have to carry it^ own oxygen supply to get around these problems, Goddard used gasoline as a fuel and mixed it with liquid oxygen. Oxygen as a gas takes up a lot of space, but as a liquid it gives the rocket a lot of energy with much less weight and volume. In 1914 Goddard patented the first liquid-fueled rocket. more...

Beta blockers are drugs that block the stimulating action of noradrenaline—the "fight or flight" hormone—thereby reducing the force of the heartbeat and the workload of the heart. Today they are widely used to treat angina, high blood pressure, and irregular heart rhythms, and to improve heart muscle function in cardiomyopathies. Beta blockers were developed in 1956 by Sir James Black [b. 1924), a Scottish doctor working for ICI in the United Kingdom. Black had personal as well as professional reasons for his interest in cardiovascular disease. His father had a fatal heart attack following a car accident, making Black ponder the role of stress in producing adrenaline, angina, and heart attacks. At the time, many of the drugs used to treat angina were vasodilators (causing dilation of the blood vessels), in particular nitrites, which increased the blood supply, and therefore the amount of oxygen to the heart. However, these caused more...

"As a physical philosopher be has no superior in our country [at least] among the young men." Geologist Benjamen Silliman on Joseph Henry When American Joseph Henry (1797-1878) first became interested in science at the age of sixteen, he found electricity fascinating and began experimenting with electromagnets. Wires carrying electricity produce weak magnetic fields around them. If, however, the wire is coiled many times around a metal such as iron, the effect is magnified and the resulting magnetic field is much stronger. The first electromagnets were coiled very loosely to prevent the current-carrying wires touching and causing an electrical short circuit. Henry was the first to use an insulating cover for the wires so that they could be wrapped more tightly and in many layers, multiplying the effect. Henry's first insulation for wires was tediously made from strips of his wife's petticoats. The material of the insulator has to resist more...

"Billy... identified [the lock] as a Chubb rather than a Bramah, which is reputably unpickable." Frederick Forsyth, The Fourth Protocol (1984) The British inventor Joseph Bramah (1748-1814) patented eighteen new ideas during his lifetime, including the fountain pen, fire engine, and beer hand-pump, but remarkably he is most famous for his safety locks. His lock design had ingeniously included notched sliders that made it nearly impossible to pick. Bramah was so sure of his locks that he offered a cash prize to anyone who could pick it open. The Challenge Lock, as it became known, caught media attention and boosted the profile of his company as the lock resisted all effort for at least fifty years; the money remained unclaimed during Bramah's lifetime. The lock was eventually opened by A. C. Hobbs, an American, although it took him sixteen days to do so. The original of the famous lock can more...

Defenses have been constructed for thousands of years. Bronze and Iron Age hillforts took advantage of natural hills for defense purposes, and the Romans built the Saxon Shore Forts along the southeast coast of Britain to deter invasion. The word fort is derived from the Latin fortis meaning "strong" and many military installations are known as forts. The term fortification also refers to improving other defenses such as city walls. Permanent fortifications were built of enduring materials, but field fortifications needed little preparation, using earth, timber, or sandbags. The arrival of cannons in the fourteenth century made medieval fortifications obsolete.  Later constructions included ditches and earth ramparts to absorb the energy of cannon fire. Explosive shells in the nineteenth century led to a further evolution; the profile of the fort became lower, surrounded by an open sloping area that eliminated cover for the enemy. The fort's entry point was a more...

In vitro fertilization involves clinicians collecting eggs from a woman's ovaries and allowing sperm to fertilize them outside of the womb. The fertilized eggs are then put back into the woman's womb in the hope that a successful pregnancy will follow. Arguably one of the most significant developments in reproductive medicine, it has been used for infertile couples the world over with more than a million babies born via the technique. Today, in vitro fertilization continues to be controversial in medical, legal, and moral terms, but it has gained wider social acceptance. The story begins with Chinese reproductive biologist Min Chueh Chang (1908-1991), who went to the United States to work with the eventual pioneer of the oral contraceptive pill Gregory Pincus after World War H. Pincus had claimed to have successfully used in vitro fertilization with rabbits in 1935. His claims were met with disbelief and neither scientist was more...

“Electrical fire would ...be drawn out of a cloud silently, before it could come near enough to strike." Benjamin Franklin, statesman and scientist American statesman and inventor Benjamin Franklin (1706-1790) was particularly interested in electricity and set up a small laboratory in his house to investigate its properties. His interest soon switched from electricity to lightning after he noticed similarities between the two. Many scientists had previously noticed a link, but none had managed to prove it. On a stormy night in 1752, he conducted a life- threatening experiment to demonstrate that lightning is the result of an electrical buildup. He constructed a kite that carried a metal spike and flew it into the thunderstorm. The kite had a key attached near the bottom of the ribbon and Franklin noticed that it sparked as he brought his knuckles close to it. Franklin had shown that lightning was a form of more...

The earliest example of a sharpened wooden pole, or spear, comes from Schdningen in Germany. There, eight spears were dated to 400,000 B.C.E. The ancient hominid hunters who sharpened each pole used a flint shaver to cut away the tip to form a point and then singed the tip in the fire to harden the wood, making it a more effective weapon. A similar technique was used by hunters in Lehringen near Bremen in Germany, where a complete spear was found embedded inside a mammoth skeleton, suggesting such spears were used mainly for hunting rather than warfare or self-defense. The need for food was so great that a mammoth would be attacked with only a flimsy spear, although its use would have been more to scare the mammoth in the direction of a trap or pit dug previously than to attack it directly. Around 60,000 B.C.E., Neanderthals living in rock more...

The dry dock was invented in Egypt by a Phoenician, some years after the death of Ptolemy IV Philopator, who reigned from 221 to 204 B.C.E. His method of launching a ship consisted of digging a trench under it close to the harbor, then making a channel from the sea to fill the excavated space with water. Dry docks continued to be used throughout antiquity. In Europe the first dry dock was commissioned in 1495 by King Henry VIII at Portsmouth, England. Dry docks are mainly used for the maintenance and repair of ships, and more rarely for their construction because the time required to build a ship is so long. While early dry docks were often used for launching ships, slipways are more frequently used in modern times. There are two types of dry docks: graving docks, where "graving" is the term for scouring aship's bottom, and floating dry more...