It's time for more science fun with Captain Zoom and her crew of human scientists, Amy and Mark, in Let's Find Out! With all of their experiments you need adult supervision!!

The RTÉjr show is produced with support from Science Foundation Ireland and it's full of fun experiments and much more. Here we learn all about bouncing!

Click here to watch the full show on RTÉ Player!

Zoom wants to know why some things are bouncy and some things aren’t - her egg for eggs-ample! She discovers that it’s all about being able to change your shape and then go back to your original shape again. So two curious kids show her how to make a bouncy ball!

Download the full lesson plan here...

You will need

  • Cornflour
  • PVA glue
  • Food colouring
  • A dropper
  • Borax salt (sodium tetraborate) - can be sourced online.
  • A jug of water
  • A tablespoon measure
  • A spoon or similar for mixing
  • A cup measure
  • Two cups


What to do:

  1. Measure 1 cup of warm water into a cup or glass and add 2 tablespoons of Borax and stir to dissolve the salt. This is the Borax salt solution.
  2. Add 4 tablespoons of PVA glue and 2 tablespoons cornflour to the other cup.
  3. Mix the glue and cornflour.
  4. Add 10 to 12 drops of food colouring to the glue and cornflour mixture and mix.
  5. Scrape the glue mixture into the Borax salt solution and slowly swirl it around.
  6. Using a spoon, remove it from the Borax solution and leave it to air dry for a few minutes.
  7. You will notice that the glue mixture has clumped together and is no longer sticky.
  8. Shape it into a ball shape using your hands and a spoon.
  9. Drop it back into the Borax solution, slowly swirl around again.
  10. Remove from the Borax solution and leave to air dry for a few minutes.
  11. Shape again if necessary.
  12. Test your ball by dropping it onto a hard surface. Does it bounce?
  13. Wash your hands after making your ball.
  14. You can store your ball in an airtight container. You will notice that it will go a little out of shape. To make it round again, simply roll back into shape with your hands when you want to reuse it.

The science bit
The Borax salt solution turns the glue into a super-stretchy solid that can be squashed and stretched and can easily return to its original shape.

It made the glue bouncy! The cornflour helped to thicken the mixture so the ball retains its shape.

Also in this episode...
The Curiosity crew have a competition to see who can design the bounciest mini egg trampoline.
And the whole crew go see a seriously impressive bouncy castle!

Click here to see all the experiments and lesson plans!