Homemade Rainbows – Science Fun for Children!

Indoors fun experiment

How about using the opportunity of an indoors rainy day to teach your children some science and some physics?

You can create your own home-made rainbow, while explaining some basic light principles! Easy-peasy and entertaining while it rains! So let’s play Sheldon from Big Bang Theory for a little bit! 😉

This activity is appropriate for older children, from 5 years upwards, but will entertain toddlers and babies and adults alike! Granted, a very young toddler might try to shove the torch in your eyes or in your mouth but the fun is all that matters!

Make your own indoor rainbow with a compact disc

You will need:

  • A compact disc (preferably one that you don’t listen to any longer!)
  • A torch
  • Kitchen foil
objects for homemade rainbow
Kitchen foil, flashlight and CD

Make a hole of about 0.5 cm in diameter in the middle of the foil. Wrap the foil over the front of the torch. Make sure the hole is over the middle of the torch

Place the compact disc on a table with the writing facing downwards.

Turn on the torch and hold it so that light reflects off the compact disc and into your eyes. You will need to have the compact disc between you and the torch and point the torch diagonally downwards.

Indoors spectrum on CD
Indoors spectrum on CD

White light: now for the science bit

Children learn all the time, so when they’re old enough to understand some basic notions of physics, you can provide them with some explanation while conducting the indoors experiment:

Most light sources, including the Sun and torches, give out white light. It is given this name because it seems to have no colour. However white light has more colour than any other type of light. White light is a mixture of many colours, from red to blue. In some situations, all the colours separate out to produce a continuous band of colour called the white light spectrum. For example, a rainbow forms when raindrops separate sunlight into a spectrum.

Indoors science activity fun
Indoors science activity fun

So how does this home-made rainbow work?

Well, the surface of a compact disc is covered with very small dents called “pits”. These cause each colour of light to reflect at a slightly different angle, producing the spectrum.

And now for some history

The first person to understand white light, was the English scientist Isaac Newton. In 1666 he performed a famous experiment in his room in Woolsthorpe, Lincolnshire.

Isaac Newton
Sir Isaac Newton (photo source Wikipedia)

He used a glass prism (as many people had done before him), to produce a spectrum of colours. Before Newton, people believed that the colours were added to white sunlight. Newton was the first to realise that all the colours are present in the sunlight and the prism simply separates them all out!

We will be trying more fun science games and experiments at home. Do let us know how your own rainbow making experiments go and if your children enjoyed them.


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