A rainbow is sunlight spread out into an arc of colours and seen by your eyes when the sun shines through water droplets

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What Makes a Rainbow?

RainbowWhere is the sun when you see a rainbow?

When looking towards the rainbow the sun is always behind you and the rainbow is alway 42 degrees from the direction opposite the light source (usually the sun).       

What makes the bow?

When sunlight hits a raindrop, part of the light is reflected, whilst the rest enters the raindrop. The light is split or 'refracted' at the surface of the raindrop.  When this light hits the back of the raindrop, some of it is reflected off the back. When the internally reflected light reaches the surface again, once more some is internally reflected and some is refracted as it exits the drop.

What makes the colours in the rainbow?

Sunlight always looks white but in fact, is made up of seven colours - red, orange, yellow, green, blue, indigo and violet. The rainbow is a whole band of colours and goes even beyond the colours that the eye can see. 

What makes a double rainbow?

Double rainbows are caused by a double reflection of sunlight inside the water droplets of the rain or spray.  All rainbows are actually double rainbows, but in many cases, the second rainbow, which is always fainter, is not visible.

Can you ever get to the bottom of a rainbow?

Even though you may be able to see someone in the distance who appears to be standing at the base of a rainbow, that rainbow will not be visible from where they are standing.  Instead, they may be seeing another rainbow at some distance further away from them.

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