World Book Trivia Challenge Advanced-5/14-inventions

Explanation
Hero lived during the first century A.D. in Alexandria. His most important invention was the screw press, a device for squeezing the juice from grapes to make wine and from olives to make olive oil. Earlier presses provided only limited pressure, and so they left much of the juice in the fruits. The screw press had a threaded shaft attached to the wood block that squeezed the fruits. By turning the shaft, greater pressure could be applied to the grapes and olives. As a result, Hero's screw press squeezed much more liquid from the fruits than earlier presses did.

Explanation
One of the most important inventions of the Middle Ages was the stirrup, which came to Europe from India by way of China. The stirrup, when added to a saddle, enabled soldiers to fight better on horseback. Before the stirrup, foot soldiers did most of the fighting. With the development of the stirrup, mounted warriors called knights became more important.

Explanation
In 1895, German physicist Wilhelm C. Roentgen discovered X rays. This discovery led to the invention of the X-ray machine. The use of X rays revolutionized medical and surgical techniques. X rays are also widely used in industry and scientific research.

Explanation
In 1909, Leo H. Baekeland, an American chemist, patented the first completely synthetic resin, Bakelite. Bakelite was one of the first plastics. In the mid-1900's, scientists working in research laboratories created synthetic fibers from such materials as acrylic, nylon, and polyester

Explanation
Another invention that uses the laser is the compact disc (CD), first sold in Japan in 1982. Most CD's measure about 43/4 inches (12 centimeters) across.

Explanation
Edward Jenner, a British physician, introduced vaccination in 1796 as a preventive measure against smallpox. By the late 1970's, smallpox vaccination had wiped out the dread disease.

Explanation
In 1709, Bartolomeo Cristofori, an Italian who built musical instruments, invented a keyboard instrument with strings that were struck by hammers. Cristofori gave his invention the name gravicembalo col piano e forte, which means harpsichord with soft and loud. The name was later shortened to pianoforte. Cristofori's instrument was the direct forerunner of the modern piano

Explanation
By around 1910, companies had created brighter, longer-lasting tungsten filaments. The first commercial fluorescent lamp was introduced in 1938 by the General Electric Company.

Explanation
Thomas Saint, an Englishman, patented the first sewing machine in 1790. It made a single-thread chain stitch to stitch leather. It fed the thread automatically to a needle which had a notch instead of an eye. An awl made holes for the needle to pass through the leather. This machine was not practical

Explanation
Muller, Erwin W., also spelled Mueller (1911-1977), was a German-born American physicist who, in 1951, invented the ion microscope. He developed it from the field-emission microscope, which he had invented in 1936.