How does a seesaw lift someone heavier than you?

Picture the seesaw at the playground, a long board that rocks up and down. You can almost feel the soft bump as your end touches the ground.

When a big grown-up sits on the other end, their side drops straight down and you hang high in the air. Yet children can still lift grown-ups on a seesaw. How does a seesaw lift someone heavier than you?

Look under the middle of the board. It rests on one strong bar called the pivot, which means the spot the board turns around. Because of the pivot, one end goes up whenever the other end goes down.

Your weight pushes your end of the board down, and the grown-up's weight pushes their end down. Their push is stronger because they are heavier. That is why you got stuck up in the air.

Here is the clever part. A push far from the pivot turns the board more easily than the same push near it. A door works the same way, swinging easily when you push by the handle and hardly moving when you push by the hinges.

So the grown-up slides along the board until they sit close to the pivot. Their weight has not changed, but now it presses down near the middle. What do you think happens to your end now?

Your end goes down! Far out at the tip, your push turns the board more than their heavier push close to the pivot. Up rises the grown-up, gently, into the air.

One word to remember: pivot. Sitting far from the pivot, your weight turns the board more than their heavier weight close to it, so your end drops and their end lifts.

Sweet dreams, and may your next seesaw ride go gently up and down.