Wednesday, 23 September 2015

Science
Why do rainbows always have the same colours in the same order?


A prism separates white light into 7 groups of colours called a spectrum. The seven colours are always in the same order. The colours are red, orange, yellow, green, blue, indigo, and violet.
I did an experiment to see If this was right and It was.I got a Prism and a tinted lense.I went outside on a sunny day, I held the prism to the sunlight and positioned it in the right place and a rainbow appeared I put the lense in front of the rainbow and it went darker.This is my explaination:

On a wet miserable day when the sun has finally there is usually a rainbow but how does it form and why are the colours always in the same order?It’s a very quick process that needs sunlight.



Rainbows are always in the same order because a prism separates white light into seven groups, this is called a spectrum.The seven groups are always in the same order.


Rainbows appear either during or after rain.The rain droplets act as a prism and reflect the sun's light which results in a rainbow.The colours are always in the same order.

The colours of the rainbow are red, orange, yellow, green, blue, indigo and violet.The colours don’t change.A double rainbow also has the same colours.A double rainbow is where a second much fainer rainbow stretches above the original one.This is caused when the light reflects twice in a water droplet.A very rare sight
is when light gets reflected three or even four times causing a triple or even quadruple rainbow.

When water splits the light ray, light is split into different wave rays.Some are shorter than others and this is how colours stay in the same order.Red has the longest ray so it can travel the furtherest.Therefore it will always form on the top of the rainbow.The shortest colour ray is voilet so it travels the lest distance and consequently will always be the inner colour of the rainbow


1 comment:

  1. Very interesting Lucy! I really like the information on the colour spectrum and why you don't usually see more than 1 or 2 rainbows.

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