Raining Rainbows: Educator Resource

Nothing brightens a rainy day like finding a rainbow! In these activities, children explore the colours and formation of rainbows, and we have collated some information to help you extend their learning and answer their questions.

Colours of the rainbow

What is a rainbow? That is a bigger question than you might think! The most straightforward answer is that rainbows are created when light is refracted, that is, it passes through a surface, and the light is bent so that it splits out into different colours based on wavelength. The colours in a rainbow will always appear in the order of their wavelength, longest to shortest: red, orange, yellow, green, blue, indigo, and violet. ‘Roy G. Biv’ is the most commonly used acronym to remember this. There are also longer and shorter wavelengths of light that we can’t see. Infrared has a longer wavelength than red, and Ultraviolet has a shorter wavelength than violet. They are both still in the rainbow, we just can’t see them!

Where do you find rainbows?

Anywhere light can be refracted and reflected. A prism is a great example where the light passes through two or more surfaces to create rainbows. Some shiny objects, like DVDs and soap bubbles, can do the same thing. You can also find rainbows almost anywhere there is bright light and water droplets in the air. This might be just as a storm is passing, in spray thrown up by a boat or by a car driving on a wet road, in the spray of a hose or sprinkler, or even from ice crystals in the atmosphere.

So what makes a rainbow rainbow-shaped?

While the light refracted through a prism is a concentrated beam, and you can hold up your hand so that the rainbow appears on your skin, the rainbows we see in the sky are an optical phenomenon and depend on where you are standing to make it visible. The familiar arc-shaped rainbow is produced when light strikes water droplets in front of you at a precise angle of 42 degrees. The light enters the water drop, refracts and starts splitting into different colours, hits the back of the water drop and is reflected, leaves the water drop and is refracted again. The light that has left the water droplet makes the rainbow.

Raining Rainbows: Reading Rainbow

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