WHAT IS THUNDER?
Thunder is the audible result of the massive and extremely rapid heating of the channel of air in which the lightning has traveled. The result is an explosion of the air. Lightning strikes and then thunder follows. Depending on your proximity to the lightning ground strike point, these may occur simultaneously (if you are very nearby) or up to many seconds later (further away) given that the speed of light travels faster than the speed of sound.
Thunder is the sound that lightning makes. Sounds simple but why does lightning make a sound. Any sound you hear is made up of vibrations, the vibrations travel through the air as waves until they reach your ear. This means lightning must cause some vibrations. Lightning is a huge discharge of electricity. When lightning strikes huge amounts of electricity shoots through the air, this causes two things to happen. 1. The electricity hits the air and starts it vibrating, anything vibrating causes a sound. 2.The lightning is also very hot and heats up the air around it. Hot air gets bigger: it expands. As lightning is very hot the air gets bigger very quickly and pushes against the air particles starting another vibration. These vibrations are what you are hearing when you hear thunder, the rumbling of thunder is caused by the vibration or sound bouncing of the ground and the clouds.
When electricity is given off through lightning, it heats the air in its path. This heating makes the air expand quickly and often violently. The molecules of heated air fly around in all directions and collide with cooler, distant air. This collision sets up a “wave” of noisy, rumbling air called thunder.
