What makes bouncy balls bounce

When a rubber ball hits something, it absorbs energy and releases energy really fast, Zheng said. If you throw the ball, the energy might come from your hands.

If you drop it, gravity gives the ball energy. And when the ball moving, it carries the energy in the form of kinetic energy. When it hits something, it stops, and the kinetic energy is stored inside the ball as internal energy.

Then it can quickly convert the internal energy back into kinetic energy which allows the ball to bounce back. You can see the ball bounce. But at the same time, there is a shift in the shape of those polymer chains.

There is something happening in the parts that make up the rubber material. The polymer chains sort of relax and then take their shape once again. If polymers are tighter together, the ball bounces higher. Knowing this, you might be able to predict what the polymers are like in, say, a basketball, a ping pong ball, or a racquetball. But what about a steel ball? Drop the balls from a specified height e.

Measure each ball three times to ensure a good average value for each ball. Compare findings to predictions and observations. Hypothesise what properties objects should have in order to bounce. Explanation: When we drop a ball and it hits the floor, some of that kinetic energy changes or deforms the shape of the ball.

Vocabulary: Elasticity : The tendency of an object to return to its original shape after being stretched or compressed. Extensions Put some of the bouncy balls in the freezer for a few hours. Take them out and bounce them again. Do they go as high when they are cold? Did any of the balls bounce higher than 1 metre? Why does this make sense? Where there any unintended energy conversions? Why can't a ball ever bounce all the way back to where it started?

Related Resources Energy Transfer Through Balls In this activity, students learn about energy transfer by observing a demonstration involving balls of different size and elasticity. Elastic Energy Ever wonder why a rubber ball bounces, or what makes a wind-up toy go? As Newton pointed out: for every action there is an equal and opposite reaction. The ball bounces off the bat and into the air. Strange as it may seem, a ball bounces off the floor because the floor pushes it up!

The Edgerton photos reveal that when a bat strikes a ball, the ball remains in contact with the bat for only a few thousandths of a second.

Imagine a baseball squashed under four tons of iron and you will begin to understand why the baseballs in Edgerton's photos are deformed. From Edgerton's photos and your observations of water balloons, you can see that balls bounce when they spring back into their original shape.

But why do some balls bounce better than others? The widely varying results of your experiments suggest that the reasons depend on a ball's materials and construction.

Footballs, basketballs, volleyballs, and tennis balls take advantage of the springiness of trapped air. When you drop a ball, gravity pulls it toward the floor.

The ball gains energy of motion, known as kinetic energy. When the ball hits the floor and stops, that energy has to go somewhere.

The energy goes into deforming the ball--from its original round shape to a squashed shape. When the ball deforms, its molecules are stretched apart in some places and squeezed together in others.