A lever is clever

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—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 it on. Suppose you want to move something

A seesaw is a lever. The rider moving down lifts the other rider into
the air.

heavy—for example, a big rock in the corner of your garden. You can
push one end of a strong board under the edge of the rock. Then you can
rest the middle of the board on a log. This will be the resting place,
or fulcrum [(fuhl]{.smallcaps} kruhm). 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 friend take turns using it as a
lever. The middle of the seesaw is the resting place. Your weight pushes
one end down and lifts your friend. Then your friend’s weight pushes the
other end down and lifts you.