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Archimedes' Principle
Archimedes' Principle summarizes how he invented a method for determining the volume of an object that has an irregular shape. To test his theory, a crown had been made from pure gold, and Archimedes was asked to determine whether some silver had been inside the crown by the dishonest goldsmith. Moreover, Archimedes had to solve the problem without damaging the crown, so he could not melt it down into a regular shape to calculate its density. Archimedes realized that the volume of the crown could be determined by the rise of the level of water it would displace, and therefore density could be calculated by dividing the crown's mass to the water it displaced. The amount of density would be higher if only pure gold was in the crown and not if dense metals were added. Archimedes was so thrilled with his discovery that he didn't bother to dress and went on the streets crying, "Eureka, Eureka!", (meaning that I found it). The experiment had shown that silver had been mixed with gold to make the crown. This principle states that an object that is plunged in a fluid produces a buoyant force that is equal to the weight of the fluid it displaces. Archimedes may have used his principle of buoyancy to determine whether the gold crown was less dense than solid gold.
Archimedes' Screw
Archimedes' work in the field of engineering mainly consisted of supplying his hometown Syracuse. Archimedes' task was to build a ship, the Syracusia, which could be used for luxury travel, carrying supplies, and as a naval warship. The ship was able to carry 600 people and included garden decorations, a gymnasium, and a temple to the Greek goddess Aphrodite in its facilities. However, since a ship would leak water through its hull, the Archimedes' screw was developed to remove water from its hull. His machine was a device with a circling screw shaped blade inside a cylinder. It was operated by hand, and could also be used to transfer water into irrigation canals. Today, we use Archimedes' screw to pump liquids and solids, such as coal and grain. The world's first steamship with a screw propeller was launched in 1839, in honor of Archimedes and his work on the screw.
Claw of Archimedes
The Claw of Archimedes is a weapon that Archimedes designed to defend the city of Syracuse. The claw consisted of a flexible metal arm with a huge metal hook. When the claw was dropped onto an attacking ship, the arm would would swing up, lifting the boat in the air and possibly drowning it.
Heat Ray
Archimedes used fire to destroy the attacking ships. He would use mirrors to angle it at the sun, and sunlight would bounce off the mirrors causing the ships to catch fire. Many scientists have tried out Archimedes' invention. A group of students in 2005 carried out an experiment with 127 sq ft. mirror tiles, focused on a wooden ship about 100 feet away. Flames caught on fire, but only after the sky had been cloudless and the ship remained still for about 10 minutes. Research carried out after this one, but concluded that the effect of the mirrors would only be possible to distract the crew with the binding, flashing light of the sun.