Question: What causes lightning?

Joe Spencer answered on 17 Mar 2015:

Lightning is just static electricity, like you get sometimes when you touch a car door, or the reason if you rub a balloon on your hair it sticks to the wall.
Lightning forms inside clouds, where dust and ice and bits bump into each other which generates an electric charge these charges move apart from each other and when they get big enough cause a spark.
Sometimes the cloud has one charge and the ground is also charged abit, this means the charge wants to move from the cloud to the ground which is a high voltage lightning strike
Hope that helps