You will need

• 1 Glass
• Milk
• Water
• Torch
• Spoon

What to do

1. Shine the torch through the beaker of water. It looks white like the sun when it is high up in the sky.
2. Pour a little milk into the water in the beaker.
3. Stir the water gently, so that it all goes slightly white.
4. Shine the torch through the water again. It will look different.
5. Again, add a bit more milk to your glass and stir again.
6. Shine the torch through the water again and observe what the light looks like now.
7. You can repeat the steps of adding milk, stirring and shining a light through several times.

Background

When the sun is low in the sky, in the morning and the evening, its light passes through more air than at other times of day. Tiny particles of air stop much of the sun’s light. Only orange and red light gets through. The same happens when you shine your light through the milk-water mixture. Tiny particles from the milk stop most of the light. Only some colours pass through. Which colours did you see?

You can watch this experiment as a video here: