Skittles experiment- how to make a rainbow on a plate

Although Hamish and I have tried this experiment before for our blog, we initially used Smarties and Rascles, both of which only let off a very light colour and when mixed did not form a bright rainbow. So, when trying with skittles today I was happy to see a brighter rainbow.

The Skittles experiment is both easy to do and low cost to try. To me, it is. Wonderful first experiment for children and it opens up opportunities for a wider observation, investigation and conversation.

Although this experiment is normally done with hot or warm water you could also try the effects using :-

  • Milk
  • White vinegar
  • Lemonade

To try this experiment yourself you will need:

  • White plate (we used a white cutting tray. We use white to allow the colours to show up better)
  • Skittles
  • Warm water


Place the skittles in a circle around the plate.

Slowly add warm water to the centre of the circle. If the skittles move a little out of place, just push them back.

Slowly watch as the colours spread. You can watch our experiment HERE

Why do the colours spread?

When the Skittles are made, they are coated in sugar and food colouring. The warm water causes this outer layer to melt and results in the good colouring dissolving into the water and defusing the colours. As these colours blend they give the impression of a vibrant rainbow.

You will however note that the colours do not blend into each other, unless the water is disturbed.

One of the reasons for this is that each colour skittles has a slightly different chemical make up and so when each colour disolves, each has slightly different properties such as salinity, density and oxygenation. This then creates a barrier preventing the colours from mixing.

Children of all ages, ( and their moms)enjoy this experiment but you could expand this for older children by:

  • Timing how long it takes for the colours to start running.
  • Use one plate with color water and one plate with warm water and discover which plate disolves faster.
  • Use different liquids.
  • Use different sweets and see their reactions.

Have you tried this experiment? Let me know how your children enjoyed this.

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