By Christina Widder a lever is

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РЕГИСТРАЦИЯ

By: Christina Widder

a lever is… • A simple machine. • A rigid bar pivoted about a fulcrum. • Broken up into three classes.

three classes of levers A first class lever is the most common type of lever.

first documented knowledge of levers • Was in 260 B. C. • By, the ancient Greek mathematician, Archimedes. • In this picture a first class lever is being used.

when was the first lever made? • The real answer is uncertain. • But it is believed that the first use of levers used trees to move heavy rocks. • Once again a first class lever is being used in the picture to the right

ancient egyptians • Levers helped build the pyramids. • Levers were used to lift large rocks for building. • Then they used other simple machines to transport those rocks.

ancient egyptians • It was estimated that it took about 30 years to build the pyramids with levers and other simple machines. • But what if levers did not exist then? • Image how long it would have taken to build the pyramids, if it was even possible.

ancient egyptians • Egyptians also used levers to move water from rivers.

ancient egyptians • This would be a lever with a counterweight. • The weight being on the opposite side of the bucket would make it easier to lift the water.

ancient egyptians • After the water is lifted, the pole is moved to the other side where the water can be put into the channel, which is then more accessible. • It was estimated that one person could lift 2, 500 liters of water a day. • Without a lever a person probably wouldn’t be able to lift as much water.

ancient romans • The first simple catapult was invented in Ancient Greece. • But the Romans used levers in making catapults with wheels, along with other simple machines.

ancient romans • The catapults were used to throw large rocks at their enemies. • Catapults helped the Romans defeat many armies.

modern scissors • Are made from two cross-blades that pivot around a fulcrum (two levers). • Were invented in ancient Rome around A. D. 100. • Scissors were typically used to make clothing.

wheelbarrow • The Chinese were credited for the invention of the wheelbarrow in A. D. 100. • The wheelbarrow is a second class lever, but also has a wheel and axle. • Was used to transport rocks, or even medical supplies during wars.

your arm is a lever • The fulcrum would be the elbow, the effort is the muscle, and the load is in the hand. • This is a third class lever. • It is unknown how long humans have been around, but we know that it has been for many, many years.

conclusion • Levers have been helpful and important throughout history. • Levers help decrease the effort it takes to move, lift, and etc… • There are many other types levers that were used in the past and are still present today; only a few were mentioned here.

work cited • Archimedes. Oct. 2006 <http: //www. sciencetrek. net/archimedes. htm> • “Catapults. ” Online Image. Hardware. fr. Oct. 2006. http: //us. games 2. yimg. com • “Castle Rock State Park River. ” Online Image. 13 Aug. 2006. Rock River. Oct. 2006. http: //pages. ripco. net/~jwn/rock. jpg • Col, Jeananda. Levers: Simple Machines. Enchanted Learning. Oct. 2006 <http: //www. enchantedlearning. com/physics/machines/ Levers. shtml> • Col, Jeananda. Zoom Inventors and Inventions. Enchanted Learning. Oct. 2006 <http: //www. enchantedlearning. com /physics/machines/Levers. shtml> • “Egyptian Pyramid. ” Online Image. A Visit to the Pyramids… Oct. 2006. <http: //members. cox. net/ancientsites/egypt/Pyramid_and_Sphinx. JPG>

Work Cited Continued • History of Levers. Science Technology and Engineering. Oct. 2006 <http: //www. enged. com. au/students/mecsys 17. html> • Johnson, Jerry. Simple machines, work… Physical Science. Oct. 2006. <http: //www. sirinet. net/~jgjohnso/simple. html> • Mc. Kee, Jeffery. “Lever. ” Online Image. Science of Evolution. Oct. 2006. <http: //home. insight. rr. com/jkmckee/lever. jpg> • “Roman Scissors. ” Online Image. Oct. 2006 <http: //www. petrie. ucl. ac. uk/detail/Images/72/UC 36207. jpg> • Simple Machines. 7 Oct. 2006. School for Champions. Oct. 2006 http: //www. school-for-champions. com/science/machines. htm • Third Class. Engine Mechanics. Oct. 2006. <http: //www. tpub. com/machines/1 b. htm> • Wheelbarrow. 7 Oct. 2006. Wikipedia. Oct. 2006. <http: //en. wikipedia. org/wiki/Wheelbarrow>

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