This post includes affliate links, read here how these work.

Rainbows have a special magic, don’t they?

The most awesome power to delight. And inspire.

And I’ve never met a child who didn’t marvel at that arc of colours in the sky when it appears.

BUT children almost just accept rainbows as something magical.

Heck, us adults do too!

BECAUSE we all struggle to get our heads around the physics behind them.

I mean, how can all those colours in a rainbow appear from transparent light?

It can kind of defies our common sense understanding of the world, doesn’t it?

SO this year, we’ve been loving this simple hands on experiment for making our very own rainbows.

 

Make Your Own Rainbows

It’s so simple, it barely feels like an experiment. But WOW it’s powerful!

We simply hung 5 little prisms in a sunny window … and waited for the sun to shine …

 
And when it does, we have rainbows. Lots of them.

We have rainbows dancing around the door frame as we come up the stairs …

 
We have rainbows on the wall …

And rainbows on the ceiling …

We even get rainbows on the floor!

And through those little prisms, we can actually see what’s going on.

And start to understand not only what makes a rainbow …

… BUT also, something very cool about the fundamental properties of light!!

 

What Makes A Rainbow?

Our little prisms helped us see that white light is actually made up of a range of colours.

Or what we call a spectrum.

When waves of light from the sun hit the prism – or a raindrop – they are bent.

Or what we call refracted.

BUT different colour light waves are bent different amounts.

Violet light bends the most. Red light bends the least.

So when light shines through a prism, bendy violet light emerges at a different point than red light.

And we can see the separate colours …

All the 7 colours of the rainbow bend slightly different amounts.

Because they have different wave lengths.

Each violet wave is shorter than the other waves and that’s why violet light bends more.

And is at one end of the rainbow.

And each red wave is longer than the other waves and that’s why red light bends less.

And is at the other end of the rainbow.

So that beautiful great arc in the sky actually appears when different coloured waves of light are bent different amounts through raindrops, depending on how long their waves are.

It’s still pretty magical isn’t it?

 

What You Need To Make Rainbows

But what do you actually need to make rainbows?

Well we filled a whole room with dancing rainbows, with just 5 little prisms that cost us the princely sum of £5! I think it’s the best 5 quid we ever spent.

They delight us every single day. And are going to buy more for other rooms.

You can get all sorts of little hanging prisms on Amazon …

We also bought one of these optical prisms to explore more when we were hooked!

They let you direct the light more so you can play with the bending.

If you manage nothing else scientific this year do make some rainbows.

It’s the most wonderfully joyful way to explore the amazing power of light!

And if you’re looking for more simple ways to explore light do check out these simple experiments … there’s more on refraction plus DIY periscopes, telescopes, kaleidoscopes and more!

AND don’t forget to save this post for later.