Presentation on theme: "By: Christina Widder. A lever is… A simple machine. A rigid bar pivoted about a fulcrum. Broken up into three classes."— Presentation transcript:
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 wouldnt 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 Scissors were typically used to make clothing.
Wheelbarrow The Chinese were credited for the invention of the wheelbarrow in A.D 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 Catapults. Online Image. Hardware.fr. Oct Castle Rock State Park River. Online Image. 13 Aug Rock River. Oct Col, Jeananda. Levers: Simple Machines. Enchanted Learning. Oct Col, Jeananda. Zoom Inventors and Inventions. Enchanted Learning. Oct Egyptian Pyramid. Online Image. A Visit to the Pyramids… Oct sites/egypt/Pyramid_and_Sphinx.JPG
Work Cited Continued History of Levers. Science Technology and Engineering. Oct Johnson, Jerry. Simple machines, work… Physical Science. Oct McKee, Jeffery. Lever. Online Image. Science of Evolution. Oct Roman Scissors. Online Image. Oct Simple Machines. 7 Oct School for Champions. Oct Third Class. Engine Mechanics. Oct Wheelbarrow. 7 Oct Wikipedia. Oct