Make a rainbow disc spinner

Planning this activity

• Decide how you’ll run the activity – the whole group could make their spinners together, or you could set up two or three experiments at the same time.
• If you have a few experiments on the go at once, put everything needed for each on a different table, and make sure there’s an adult at each table. Decide how you’ll signal that everyone should move to the next table and start the next experiment.
• Make spinners out of white card. You could use the spinner template, or draw around something round (such as a plastic beaker) then draw lines using a ruler to divide the circle into six sections. Both sides should be divided into six equal sections. Cut the circles out.

Make the spinners

1. Give everyone a spinner. It should be a cut-out circle of white card, and each side should be divided into six equal sections (a bit like a pizza!).
2. Everyone should colour both sides of their spinner. They should make sure each section is a different colour. People can choose which colours they’d like, but bright colours work best.
3. Encourage people to be creative, and think about putting light colours next to dark colours.
4. Everyone should work with an adult to make two holes near the centre of the wheel. They could put a small piece of sticky tack underneath the wheel, then use a skewer (or sharp pencil) to pierce the holes. The templates have dots to show you where to make the holes.
5. Now measure around 60cm of thing string. That’s roughly the length of an adult’s arm, from the tip of their middle finger to their shoulder.
6. Next, thread one end of the string through both of the holes, so one side of the spinner has a loop of string and the other side has two loose ends. They should tie the two loose ends together, so the spinner is in the middle of a big loop of string.

Try the spinner

1. Everyone should wind the wheel on the spinner several times. The more they wind the wheel, the better it will spin.
2. Hold the ends of their string, then pull their arms apart to make the wheel spin around. They should look closely at the wheel – what colour do they see? When it’s moving really fast, the circle will look white.
3. Everyone should think about why they only see the colour white. They may want to talk to a partner to share their ideas. Does the ink fall off the paper? Do the colours actually disappear? Is our mind just telling us it’s white?
4. Now repeat steps one and two to spin the spinner again and try to figure out what’s happening.
5. Everyone should gather together. The person leading the activity should help everyone talk about what they saw, and why they think it happened. The ink didn’t fall off the paper; it was still there at the end. No one suddenly became colour blind; they could see other colours in the room.
6. Explain that the spinners looked white because our eyes can’t keep up with how fast the colours were spinning, so it combined them and blended them into one, and the spinner looked white.
7. A scientist called Newton used a coloured circle like this to show that sunlight is made up of all of the colours of the rainbow added together to make white light.