Science Experiment – Galaxy

By AG Education 13 December 2017
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Simulate a spiral galaxy inside a cup

About this experiment

Elliptical, irregular, and spiral are the three main types of galaxies in our universe. The majority of galaxies – including our own, the Milky Way – are spiral galaxies. They have arms of gas and dust that are tightly wound around the centre of the galaxy, which causes the appearance of a spiral. You can create a similar-looking effect with just a few materials in this experiment.


  • A few plastic cups
  • A teaspoon
  • Water
  • ½ tsp powdered milk
  • Food colouring


  1. Fill three cups about halfway with water and add a few drops of food colouring. Carefully grab one cup and move your wrist in a circular motion to swirl the water inside the cup. Once the water is really swirling, place the cup on a flat surface so that the water is still moving when it’s set down.
  2. Next, sprinkle about half a teaspoon of powdered milk over the centre of the cup. Observe the spiralling pattern of the powder as it swirls around in the water.
  3. Repeat the previous steps for water that is turning at faster and slower speeds.

How do the patterns differ in each cup?

When the water is swirling faster, the powder creates a tightly wound spiral around the centre. This looks a bit like tightly wound spiral arms in a quickly turning spiral galaxy.

Do you want to keep learning? Find more experiments here!