Lever facts for kids
Quick facts for kids Lever |
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Levers can be used to exert a large force over a small distance at one end by exerting only a small force (effort) over a greater distance at the other.
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| Classification | Simple machine |
| Components | fulcrum or pivot, load and effort |
| Examples | see-saw, bottle opener, etc. |
A lever is a simple machine. It consists of a beam connected to ground by a hinge, or pivot, called a fulcrum.
The lever can be used in a lot of ways. One way is by measuring things, or by seeing which weighs more.
It is one of six simple machines. There are three types of levers: first-class, second-class and third-class.
Contents
Etymology
The word "lever" entered English around AD 1300 from Old French. This sprang from the stem of the verb lever, meaning "to raise". The verb, in turn, goes back to Latin: levare, itself from the adjective levis, meaning "light" (as in "not heavy").
Early
The earliest remaining writings about levers are from the 3rd century BC. They were written by Archimedes. "Give me a place to stand, and I shall move the earth." is a famous quote from Archimedes who stated the correct mathematical principle of levers (quoted by Pappus of Alexandria).
Types of levers
There are three kinds of levers. The difference between them is where the fulcrum is and where the forces are.
First class
A first-class lever is a lever where the fulcrum is in between the effort and resistance (the load). Seesaws and crowbars are examples of first class levers.
Second class
A second-class lever is where the resistance is between the effort and the fulcrum. Wheel barrows and wrenches are examples of second class levers.
Third class
A third class lever is where the effort is between the resistance and the fulcrum. Staplers and your forearm are examples of third class levers.
Images for kids
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A lever in balance
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Three classes of levers
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Archimedes lever, Engraving from Mechanics Magazine, published in London in 1824
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Simple lever, fulcrum and vertical posts
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See also
In Spanish: Palanca para niños
