The Play Area

If you’re sitting on the swings can you swing back to as high as when you started?

(Image courtesy of Creative Commons: http://www.flickr.com/photos/vanz/)

If you sit back on the swing and let someone give you a push, you’ll notice that you’ll never be able to reach that high again. If you swing your legs then you’ll see that you can make the swing go higher.

What’s going on?

The air that surrounds you is made up of tiny particles. When you move through the air you bang into the air particles which very slightly slow you down. Without swinging your legs, the swing won’t reach the same height because the air slows you down too much for you to reach that height again.

What happens when you swing your legs?

To understand how swings work we have to talk about different types of energy. The swing relies on two different types of energy, potential and kinetic. Potential energy is the energy stored in a system. In this case the energy is stored at the high part of the swing. Kinetic energy is the energy used when you move. As you swing energy is changed from being potential energy into kinetic energy. The amount of energy that is stored in each swing depends on how high you swing to. By raising your legs you make yourself a little bit higher which gives you more potential energy and so more kinetic energy and you’ll swing higher.