Friday 17 April 2015

A Lever Is Clever

How many times can your lift your friend higher than your head? How many times can your friend lift you? It doesn’t sound easy, but it is – and it’s fun too. When you and your friend are on a seesaw, that’s exactly what you are doing!
The seesaw you and your friend are riding is really a kind of machine called a lever. A lever makes pushing and lifting easy, even when things are hard to move. The simplest kind of lever is just a straight stick or board and something to rest on. Suppose you want to move a big rock in your garden. You can push one end of a strong board under the edge of that rock. Then you can rest the middle of the board on a log. This will be the resting place, or fulcrum. The end of the board near you will stick up. Now push down on the high end of the board. The other end will move up – and the heavy rock will move too.

When you ride a seesaw, you and your friends take turns using it as a lever. The middle of the seesaw is the fulcrum. Your weight pushes one end down and lifts your friend. Then your friend’s weight pushes the other end down and lifts you.
Have you tried to dislodge a nail using the claw of a hammer? It would be extremely difficult to do it with just your bare hands. The head of the hammer that rests on the board acts as a lever, and when you pull the hammer’s handle down, the claw will easily lift the nail out from the wood.

Experiment: To construct a tool that uses a lever (Lever crocodile)

6 strips of cardboard (6cm long and 2cm wide), 7 paper fasteners, scissors.

1. Arrange the 6 cardboard strips into three X shapes in a row.
2. Poke through the 7 paper fasteners where the cardboard strips overlap.
3. Make a crocodile head out of construction paper and attach it to one end of the tool.


Fulcrum [fuhl-kruhm] point of rest on which a lever turns.

Shared by Surain A. Victor
Guest blogger

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