Why is there lightning and thunder?

Basically lightning is caused by build up of electron in the cloud and the lack of electron in the ground. A charge of electrons is continually building up in the clouds while lack of electrons occurs on the ground. When this process (the build and the lack) is large enough, there will be a large of energy stored which will be release at once, This will force an electric current through the sky that will allow the charges to neutralize. Most of this energy is turned into heat and light, thus lightning is produced. On the other hand, thunder is created when the lightning passes while heating the air it passes. As the air is heated by the lightning, the air expands and presuure builds up. Eventually this pressure will explode creating the thunder. (Just like a balloon when it pops up due to pressure).

hmmm this is a cool science question, but i think the best person to answer this is Thor himself XD do you agree? :P

I'm scared of lightning, too, but that's just the way nature is wired and we can't do anything about it. Lemme see if I remember my grade school science. The clouds in the sky have positive (or is it negative?) charges. And so when they hit the negative (or positive) charges, electricity is produced and so there is lightning. The thunder is the effect of the lightning when it heats the air around it. Gee, I'm not sure if this is entirely correct but, somehow that's how I remember it. I hope somebody geekier here set things straight.

I'm not really that scared of thunder but I hate it when it's near, especially when it is really loud and you can see it flash near you. I guess lightning or thunder is caused by two clouds 'colliding' to each other. Sometimes, I would have hard time sleeping whenever there is lightning. I really do not want lightning or thunder flashing towards me. It looks scary by the thought of it.