Use science (and a bit of food colouring) to make a beautiful rainbow by “walking” colours between glasses.
What you need:
- at least 3 glasses or jars, 5 glasses is better but you could also use 7 – it is best to use small glasses/jars
- red, yellow and blue food colouring
- paper towel
- water
What to do:
- Put your glasses or jars in a row, right next to each other.
- If you have five glasses, place red food colouring in the first glass, yellow in the third and blue in the fifth one. If you have seven glasses, add red to the seventh glass. You will need to use approximately twice the amount of yellow colour to that of blue and red.
- Fill each glass with colouring with water. Make sure you fill it to the top. Do not put anything in the empty glasses.
- Fold sheets of paper towels over about four or five times to get long strips.
- Bend the paper towel in half and place paper towel between each pair of glasses.
- Sit back, wait and watch.
What happens:
The paper towel will absorb the water (and the food colouring) from the full glasses. The water will run the length of the towel before dripping into the empty glasses. This will continue until there are equal amounts of water in all the glasses. The different food colours will mix together, giving a rainbow (eg. red and yellow will mix to form orange, yellow and blue will mix to form green). This will work with big glasses, however the more water you use will require more time, so it’s best to use small containers.
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