"Give me a lever long enough and a fulcrum on which to place if and I shall move the world" Archimedes, mathematician and physician The lever was first described in 260 B.C.E. by Archimedes (c. 287-212 B.C.E.), but probably came into play in prehistoric times. A lever can be used to raise a weight or overcome resistance. It consists of a bar, pivoted at a fixed point known as the fulcrum. Extra power can be gained for the same effort if the position of the fulcrum is changed. Levers may be divided into classes. First-class levers have the fulcrum in between the applied force and load, which are at opposite ends, such as with the seesaw. Second-class levers have the fulcrum at one end, and the applied force at the other, such as with a bottle opener. Finally, third-class levers have the effort in between the fulcrum and the load; more...

"Any of us who [have walked] away from an automobile accident is likely to have a dummy to thank." JackJensen, General Motors In the fate 1940s, the U.S. Air Force wanted data on how deployment of their newly designed ejection seats would affect the pilots who were strapped into them. For the first time, a crash test dummy was created to obtain the information. This very smart dummy was named "Sierra Sam" and was built in 1949 by American Samuel'- Alderson (1914-2005) in partnership with the Sierra-engineering Co. Prior to the arrival of the crash test dummy, human cadavers were used to guide safety design. Working with corpses was of course highly unpleasant, but also the human bodies were very limited in terms of the information they could convey to researchers. It was also impossible to use them repeatedly to any useful purpose, and although they gave limited information on more...

A war is never a good thing it takes away hundreds of lives. Leaving behind  thousands of widows and orphans. The financial burden due to war affects the economy of the country and development of country lacks behind. Since independence Kashmir has always been a bone of contention between India and Pakistan. Pakistan has desired to grab Kashmir, an integral part of India. She fought many wars against India but always lost them due to excellent bravery of our soldiers. On the other hand India has always tried to reconcile and wanted normalcy in the island. The Indian Government has declared time and again for maintaining friendly relations and peace with the neighboring countries. It has no intention of interfering in the internal affairs of any other country. But after Pakistan lost every war they started terrorism by sending intruders in India specially in Punjab and Kashmir to achieve their more...

The simple pulley enables the user to lift a load more easily by changing the direction from which the force is applied. When the rope is fixed at one end and another pulley is added, the system provides a mechanical advantage by multiplying the applied force, making it possible to lift heavy loads. More pulleys can be added to the system, now known as a "compound pulley" system, further multiplying the effectiveness of the force applied. As an indication of the benefit of the system, the addition of a second pulley to a one-pulley lifting mechanism halves the amount of force required to make the lift. A third pulley, properly rigged, reduces the amount of force required to a quarter. In 250 B.C.E., the Greek scientist and.-, .inventor Archimedes (c. 287-212 B.C.E.) adopted this principle by mounting several pulleys on the same axle to create a "block" that was much more...

"Slebe's design... remained In use essentially unchanged by the Royal Navy until]989." English Heritage The standard diving suit, or "hard-hat" diving suit, was a major advance in diving technology. Early diving suits were crude and inflexible and imposed major restrictions on divers' movements, such as an inability to invert. A brilliant German inventor by the name of Augustus Siebe (1788-1872) changed all that with his innovative "closed" helmet suit—a design that remained essentially unchanged until fiberglass SCUBA suits arrived in the 1960s. After learning metal craft and working as a watchmaker, and following service as an artillery officer in the Prussian army at the Battle of Waterloo, Siebe moved to England in 1815. While living in London he stumbled across the solution to creating a more practical diving suit. Previous designs—so- called "open dress" suits—were simple diving bells that trapped air for breathing, but these took in water when the more...

In the early 1940s plastics were still relatively new compounds and their practical applications had not yet been fully realized. Early plastics were brittle, greasy, and had a rather unpleasant odor. It would take an ex-tree surgeon by the name of Earl Tupper (1907-1983) to come up with the perfect plastic. Tupper worked at the chemical company DuPont, where he learned about the design and manufacture of plastics. In 1938 he founded the Earl S. Tupper Company, which manufactured parts for gas masks during World War II. After the war, he turned his attention toward creating a peacetime product. Tupper discovered a way of turning polyethylene slag—a by-product of crude oil refinement—into a strong, resilient, grease-free plastic that he called Tupperware®. By 1946 Tupperware® was on the market in an array of brightly colored incarnations: cigarette cases, water tumblers, and food storage containers. In 1947 he patented the Tupperware® seal, more...

Needle and pill phobia sufferers must have cheered when the U.S. Food and Drug Administration (FDA) approved the first transdermal patch in 1979. This new mode of drug delivery promised all the benefits of shots and pills but with no downside. Patient comfort was not the reason biochemist Alejandro Zaffaroni (b. 1923) developed transdermal patches. Zaffaroni wanted to mimic the body's timed release of hormones and thought available drug delivery methods were not sophisticated enough. In 1969 he started his company, ALZA, and by 1971 had been awarded a U.S. patent for a "bandage for administering drugs." Big pharmaceutical companies thought the patch was the path to nowhere. "I thought the industry would look at what we were doing and say, 'Gee, it makes a good deal of sense. But they didn't,'" said Zaffaroni in an interview. The pharmaceutical industry, however, soon realized that Zaffaroni's patches made good sense and more...

"[It was on this day] I suddenly knew how to make a one-step dry photographic process." Edwin Land The "Polaroid" camera became an instant classic following its conception, more than sixty years ago. Although the technology behind self-developing film was already present at the time, it was Edwin Land (1909-1991), founder of the Polaroid Corporation, who designed and produced the first commercially available self-developing camera in 1946, an invention that won its creator many accolades. Land formed his company in 1937 to produce and sell the polarizing filters he had patented eight years before, and soon the company was making filters for the United States in World War II. Land was on vacation with his daughter in 1943 when, after snapping a photo of her, she asked why she had to wait so long to see the image. He soon visualized a system of "one step dry photography," whereby the more...

"A chair is a very difficult object. A skyscraper is almost easier. That is why Chippendale is famous." Ludwig Mies van der Rohe, architect Chairs have been invented that swing, swivel, rock, roll, recline, fold, massage, and even electrocute. Before all of those, however, came the invention of the chair in its simplest form, about 4,800 years ago. More than a thousand years before that, man had invented a way of resting in a sitting position off the floor, on the simple backless seats known as stools. Stools were raised to an art form by the ancient Egyptians. Beside creating beautiful and ornate stools, the Egyptian craftsmen also focused on function by fabricating stools that folded. Some examples have floor rails and crossing spindles with carved goose heads inlaid with ivory to resemble feathers and eyes. In the Third Dynasty (2650-2575 B.C.E.), Egyptians were also to give stools their greatest more...

The proverb "All work and no play make Jack a dull boy" is quite correct. This shows the need for rest, recreation and fun after doing hard work. Tiresome and constant work becomes a burden if we fail to get rest. So holidays are necessary. They remove fatigue from our body- They give comfort to our mind. There are two kinds of holidays—(i) Short holidays and (ii) long holidays, Sunday is a short holiday. It gives us time to do our urgent work which we cannot do on account of busy life and routine work. We got long holidays on the occasion of festivals. Generally, such holidays are spent in celebrating festivals or to get recreation. Students get summer vacation which lasts for two months. We must use long holidays in a proper way. A programme must be chalked out to make use of them. Often teachers prescribe home work more...