Why is the sky blue?
Part of the show Forecasting weather and climate
What you need
A lemonade bottle or large glass
A large jug or a bowl and a funnel.
Water
A little milk powder
A small powerful torch
A dark room
What to do
Fill the jug with water
Add the milk or milk powder - do this very slowly as you only need a tiny amount. 5-10 pinches will probably be sufficient
Turn the lights off
Pour 1-2 cm of liquid into the bottom of the bottle.
Shine the torch up through the bottom of the bottle.
Look at the light coming straight through the bottle and the light coming out of the side, what happens to the colour?
Add some more liquid, and look thorough it again (repeat)
If nothing happens to the colour, you need to add a bit more milk powder, if the light doesn't get through the bottle, you need a bit less
What may happen?
The more milk the light goes straight through, the redder the light should look. So with no milk the light bulb will probably look white, then go through yellow, orange and if you are lucky end up looking red.
If you look at the side of the light beam, you may notice a blueish tinge to the light coming out of the side near to the torch and the scattered light will look more and more reddish the further the light travels through the liquid. You may have to shine the torch into the side of the bottle to make a clean enough beam to see this.