How to make a rainbow

Learn how to make a rainbow with this fun learning activity for KS1 and KS2 children to learn about light and the weather.

Make a real rainbow with a hosepipe

If you have a hosepipe that can make a fine mist of water ( or a spray bottle ) you can make an actual rainbow you can easily see.


Hosepipe or Spray bottle


Stand with your back to the sun and spray your hosepipe in a fine spray into the air in front of you in different directions to see where the best rainbows are.

Make a rainbow

Why Does this Happen?

The small drops of water behave just like a prism, bending the different colours of light by a different amount and so splitting the light into individual colours.

This happens because light is made up of different wavelengths, each of which bend by a different amount when they pass through a prism or raindrop. Violet light is bent the most and red the least.

We call the bending of light refraction and the splitting up of light into a rainbow of colours is called dispersion.

The colours of the rainbow are:

Red, orange, yellow, green, blue, indigo and violet

Can you think of a fun way to remember the order of the colours?

rainbow art

Rainbow Crayon Resist Drawing

This is a great way to write a secret message to a friend or just for drawing a picture with a difference. We drew a rainbow behind a cloud to illustrate how it works.

What you need

White paper or card
Crayons or water based paint


Use the white crayon to draw a cloud, pressing down hard.

Using coloured crayons draw a rainbow over your cloud.

You should find that the cloud stays white even though you crayon over the top.

Why does this happen?

The thick waxy crayon resists the colouring over the top allowing you to see the white cloud.

If you paint over the cloud, the same should happen as the crayon repels the water-based paint.

Extension ideas

Would a wax candle work better than crayon?

This post was written by Emma of Science Sparks

emmavEmma is a busy Mum to three who is passionate about science education. You can find Emma’s experiments and activities over at Science Sparks which is full  of fun, creative and engaging science based activities for children of all ages, perfect for home or school. Find out more at Science Sparks


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