Question: what causes lightning?

Fiona McLean answered on 22 Jun 2014:

This is a great question! So lightening is basically what happens when you get an electric shock off a woolly jumper but on a much bigger scale.

First a cloud is made. This happens when hot air with water vapour in it rises from the ground up high into the sky where it cools down and forms a cloud. If the cloud is really cold then the water vapour freezes and turns into ice. These bits of ice then bump into each other and build up electric charges. These include positively charged particles (at the top of the cloud because they are lighter) and negatively charged particles (at the bottom of the cloud because they are heavier). When the charges are big enough it makes a spark which is the lightening. This type of lightening is called sheet lightening.

The other type of lightening is fork lightening and this is the lightening that you see between the sky and the ground. This happens the same way as sheet lightening but the positive charges build up on the ground (around an object such as a tree or even a person!) and the reaction is with the negative charges in the bottom of a cloud.

Crazy stuff!

If you want to make you own lightening then this is a good website to tell you how to do it:

http://www.planet-science.com/categories/under-11s/our-world/2011/05/what-is-lightning.aspx

You can also do it with a balloon and spoon. Get a balloon, rub it on your hair lots then hold it near the spoon (it’s easier to see in a dark room)!