Why do balls bounce?

This week we are investigating how different balls bounce differently on different surfaces.

Balls bouncing seems like a simple concept, but the science behind it is quite complicated, so please bear in mind that we have simplified it for our audience.

I asked the children to choose three balls of different sizes and this is what they came back with.  Not only were they of different sizes they were also made of different materials, ranging from soft to very hard.

We decided to test the balls bouncing on three different surfaces:

  • carpet
  • wood
  • tiles

The balls are all made of different materials which needs to be considered, so we talked about what we could keep constant.We decided that the height from which the balls were dropped was important as was the force with which they were dropped.

Why do balls bounce?

My 5 year old dropped all the balls from shoulder height each time, and tried to just drop  without any extra force.

Each time we recorded into a simple table how high the ball bounced.

Why do balls bounce?



We found that all balls bounced higher on the tiles than any other surface and lowest on the carpet. The smallest (hardest) ball reached the greatest height on the hard surfaces.

The science bit

So, why do balls bounce?

The reason balls bounce is quite advanced science.  It relates to how much energy balls have, what they are made of, how they change shape and where the energy they have goes.  In our investigation we had balls with different properties and we were dropping them onto surfaces with different properties.  The children were oblivious to these differences but did expect the bouncyness to relate to the size of the ball which is not necessarily a factor. There is much room for improvement on our investigation. How would you go about making this more scientific?  We just liked throwing balls around :)


For older children

You could record the number of bounces on each surface for each ball.

Try dropping the balls from different heights, what happens?

Can you get three balls of different sizes made from the same material and see what happens?

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Author: Emma Vanstone

Science Sparks, is a site dedicated to making Science fun for kids. I’d love you to follow me on my Google Profile+.

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  1. I think you did a great job with this experiment for a very young child. My kids are a little older and I have thought about doing something similar. I was thinking we would drop different types of balls off the balcony and try to measure how high they bounce with a tape measure. I’m interested to see the responses you get to your question.

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  2. Yet another fun way to introduce science with a favorite play item! Thanks for sharing.

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  3. What a fun experiment. Thank you for sharing at Sharing Saturday! I hope you are having a wonderful week!

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