Our boys have become interested in space and have borrowed many books from the library on this topic. While thinking of activities we could do that go with this topic, we decided to do a twist on this Nervous Colours experiment, creating some Swirly-Whirly Planets.
Swirly, Whirly Planets
What you need:
- washing up detergent
- cotton buds
- 8 containers / lids (9 if you want to make the Sun)
- food colouring
What to do:
Pour just enough milk into each of the containers, so that it just covers the bottom.
Add a few drops of food colouring to each container. For Mercury we used red and yellow, Venus we used red, peach and yellow, Earth we used green and blue, Mars we used red, Jupiter we used yellow, red and blue, Saturn we used red and yellow, Uranus we used blue and Neptune we double the amount of drops of blue food colouring than we used in Uranus.
Here’s the fun part! Dip a cotton bud into washing up detergent and touch the milk with it. Watch the colours swirl and whirl around!
Making Venus (above).
The more you touch the cotton bud to the milk, the more the colours would mix.
Slowly, the kids completed all the planets.
How does this work?
The molecules of the milk and the food colouring are always pulling on each other. This pull is called surface tension. When you add the washing up detergent, it stops the molecules clinging together and they spread out. The surface of the milk moves about creating patterns with the food colouring.