by: christina widder
DESCRIPTION
Levers in History. 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. - PowerPoint PPT PresentationTRANSCRIPT
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By: Christina Widder
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A lever is…
• A simple machine.
• A rigid bar pivoted about a fulcrum.
• Broken up into three classes.
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Three Classes of Levers
A first class lever is the most common type of lever.
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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.
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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
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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.
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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.
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Ancient Egyptians
• Egyptians also used levers to move water from rivers.
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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.
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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.
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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.
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Ancient Romans
• The catapults were used to throw large rocks at their enemies.
• Catapults helped the Romans defeat many armies.
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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.
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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.
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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.
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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.
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Work Cited• Archimedes. Oct. 2006 <http://www.sciencetrek.net/archimedes
.htm>• “Catapults.” Online Image. Hardware.fr. Oct. 2006.
http://us.games2.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/ancient-sites/egypt/Pyramid_and_Sphinx.JPG>
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Work Cited Continued• History of Levers. Science Technology and Engineering. Oct. 2006
<http://www.enged.com.au/students/mecsys/mecsys17.html>• Johnson, Jerry. Simple machines, work… Physical Science. Oct.
2006. <http://www.sirinet.net/~jgjohnso/simple.html>• McKee, 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/UC36207.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/1b.htm>• Wheelbarrow. 7 Oct. 2006. Wikipedia. Oct. 2006.
<http://en.wikipedia.org/wiki/Wheelbarrow>
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