Skittle Rainbows

Try this awesome experiment and watch a colourful display unfold before your eyes!

You will need

  • A pack of Skittles
  • A plate
  • Some water

Method

  • Place the skittles around the edge of a plate. The edge of the inner rim is best.
  • The skittles can be arranged in any way, so this is great for the children to be creative and decide themselves. They can be arranged either in colour groups or a repeating pattern or even better…just random. The Skittles should be touching.
  • Into the centre of the plate pour some water. Pour the water in gently and just enough so it reaches out and touches all the skittles at the edge of the plate.
  • Now watch…. After a short while you will begin to see the colours from the skittles dissolving into the water and after about 5 minutes a beautiful rainbow pattern will have been made.
  • It’s really important not to jog the plate when this is happening as the colours can muddle up.

Investigation

  • What if you use warm water? Is it better than using cold water?
  • What happens if you leave spaces between the skittles? Does is still work?

Science

You may wonder why the colours don’t mix up as the rainbow forms… well here’s the science. The colour and sugar from the skittles dissolve in the water. These dissolved molecules will move from a high concentration (by the skittle) to a lower concentration (towards the centre of the plate) – this is called diffusion. As there are multiple bands of coloured water all doing the same thing, they don’t travel sideways (because there is already a high concentration of sugar and colour sideways). Instead they all move towards the centre. Diffusion can also be demonstrated by squirting perfume at one side of the room and counting how many seconds it takes to travel to the other side of the room (another fun thing to try).

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