How many times can you lift your best friend higher than your head? How many times can your best friend lift you? It doesn’t sound easy, but it is. 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 heavy and hard to move.
The simplest kind of lever is just a straight stick or board and something to rest it on. Suppose you want to move something heavy – a big rock for example. You can push one end of a strong board under the rock. Then you can rest the middle of the board on a log. This is the resting place, or fulcrum. The end of the board near you sticks up. If you push down on the high end of the board, the other end will move up. The heavy rock will move, too.
Archimedes, an ancient Greek scientist, was the first person to describe how levers work. To prove the power of levers, he built a machine that he used to launch a ship all by himself.
When you ride a seesaw, you and your friend 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 up. Then your friend’s weight pushes the other end down and lifts you up.
Picture Credit : Google