Homemade Sunset

What you need

• A large clear, straight-sided glass
• Water
• Milk
• Teaspoon
• Torch
• Darkened room

Instructions

1. Fill the glass about two thirds full of water
2. Add half a teaspoon of milk and stir
3. In a darkened room, shine the torch down onto the top of the water while looking through the side of the glass. Can you see the blue colour?
4. Now try shining the torch through the side of the glass while looking through the opposite side. What colours can you see now?
5. Finally, shine the torch up through the bottom of the glass and peer down through the water

Results and Explanation

While shining the light up through the bottom of the glass, you should see a 'homemade sunset'. The milk particles in the glass scatter the light in the same way that dust and particles in the Earth's atmosphere scatter light from the sun. The further the light has to travel through the water, the more of the blue light is scattered, leaving only red light for you to see, just like at sunset.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.