What you need
- Torch* (you can use the torchlight function in mobile phones)
Place your prism on the window ledge. Adjust position of the prism until light falls onto the prism and a rainbow appears.
Hold your torch with one hand and the prism in the other. Twist and adjust the position of the prism until it catches the light and a rainbow appears! Project your rainbow onto a piece of paper and fill in the colours according to what you see on the paper!
A rainbow is created when white light is bent (refracted) while entering a droplet of water, split into separate colours, and reflected back.
Water and other materials bend the different colours at different angles, some more strongly than others.
When the light enters the prism, it bends. The 7 colours separate and a rainbow appears!
What you need
- Food colouring** (red, yellow and blue)
**Items provided in the Colour Mixing Challenge
Step by step
1. Place the 7 cups in a row and fill the first, third, fifth and seventh cup with 80ml of water.
2. Add 5 drops of red food colouring to the first and seventh cup. Stir evenly.
3. Add 5 drops of yellow food colouring to the third cup and stir evenly.
4. Add 5 drops of blue food colouring to the fifth cup and stir evenly.
5. Take a filter paper and fold it into half and in half again lengthwise. Repeat until you have folded all 6 filter papers.
6. Place one end of the folded filter paper in the first cup and the other end in the second cup (make sure the ends of the filter paper touch the bottom of the cups).
7. Continue Step 6 until you have placed the last filter paper in the sixth and seventh cup.
8. Observe and watch the rainbow relay happen right before your very eyes!
The filter paper is made from fibres and the water is able to move through the gaps in the fibres. The gaps in the filter paper help to pull the water upwards.
Each raindrop makes its own rainbow but it takes millions of raindrops for us to see a rainbow.
There is no end to a rainbow. Rainbows are actually full circles. We only see an arc (part of the circle) because we usually view rainbows from the ground.
Occasionally, passengers in a low-flying aircraft see rainbows that form complete circles!