9 Answers To Science Questions You All Had As Kids

8. Why Is The Sky Blue?

It's a classic.

White light is made up of a spectrum of colours. Each of these colours has a different wavelength and will therefore interact with the atmosphere differently.

The molecules in the air, mostly oxygen and nitrogen, are tiny compared to the wavelengths of light and will scatter shorter wavelengths more easily.

Blue light has a particularly short wavelength and is therefore scattered much more by the particles in the atmosphere as it bounces off them. Light is actually invisible until it bounces off something, so this scattering makes only the blue light visible.

As the sun sets, its light has to travel through even more of the atmosphere before it reaches you. This scatters the blue light so much that barely any of it actually ends up reaching you and you are just left with the colours with longer wavelengths - the yellows and reds.

Look at a particularly dramatic sunset and you will probably be able to pick out most of the colour spectrum for a rainbow/sunset double whammy.