Step aboard the Spaceship Curiosity with Captain Zoom and her human crew, Amy and Mark, as we discover science in Let's Find Out!

Tune in to RTÉjr weekdays at 7am and 2.30pm or watch it any time on RTÉ Player!

The fun RTÉjr show is made with support from our friends at Science Foundation Ireland and we are sharing loads of great experiments from the show here.

Here, Zoom wants to find out more about foam so Ellie and Caoimhe use shaving foam to make their own colourful rain...

It's the rain in a jar experiment...it is messy and we always say to have an adult supervising!

You will need

  • A glass jar
  • Some water
  • A can of shaving foam
  • Blue food colouring
  • A dropper (these can usually be purchased from a local pharmacy); the dropper is only used to add the food colouring; if your food colouring bottle contains a dropper then use that.
Zoom always asks loads of great questions!

What to do

  • Fill the glass jar about two-thirds full with water.
  • Shake the can of shaving foam well and then spray foam on the top of the water so it fills the glass. It will look a bit like a cloud sitting on top of the layer of water.
  • Using the dropper, add some drops of blue food colouring into the layer of foam. Add the drops near the top of the foam layer.
  • Watch what happens to the drops of food colouring.

The science bit

The food colouring moves slowly through the foam but it doesn’t mix with it… the foam is so thick that the food colouring stays as drops and slowly passes through it. The foam acts like a solid.

But once the drops of food colouring pass into the water they can move more quickly so they streaks through it, and look like rain.

The water is a liquid and the food colouring will eventually mix with it turning all the water blue.