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Rainbow

Rain Fall

A rainbow is an arc of color in the sky that you can see when the sun shines through falling rain. The pattern of colors starts with red on the outside and changes through orange, yellow, green, blue, indigo to violet on the inside.

Sunlight is made up of rays in different colours

Normally we perceive the light from the sun as without any colour, but actually it consists of many different colours, the same colours you can see in a rainbow. The combination of these colors seems white to us.
So it just the opposite from when you mix 10 different water colours together and the result is a slushy brown!

Rainbows need rain and sun

You are able to see all the colors of the sunlight when certain weather conditions occur.
The sun shouldn't be high in the sky but a bit lower (this is why in summer you see rainbows only in the mornings or evenings).
There also has to be rain, preferably a heavy one.
At the end of the rainfall, when the sun starts to peek through the clouds again, you may sometimes see a rainbow if you turn your back to the sun and look into the rain.

The raindrops reflect the sunlight as if they are millions of little mirrors.
In each raindrop the different colors in the sunlight get reflected differently and this means that the light of the sun is perceived differently by you. The different colours don't get mixed to the usual "white" light as ususal but they hit your eyes like seperate colours.

Why are rainbows rounded?

You have to stand in a certain angle to the rainbow in order to see it. This is just like with a mirror: You have to stand in front of it to see your own reflection. The rainbow needs an angle of 42 degrees and this can only be achieved in a circle of which you can see half on the horizon. Yes, a rainbow is actually a circle! On the ground, the bottom part is hidden, but in the sky, like from the view of a flying airplane, it can be seen as a round shape.

The rainbow effect can also be observed when there are other water drops than from rain in the air; for example another common place to see the rainbow effect is near waterfalls or fountains

You can even make your own rainbow: On a sunny day, go into the backyard and take a water hose with a spray nozzle. Turn your back to the sun and spray water into the air. Look into the water mist and you will see a very small DIY rainbow!

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