Thunder

Thunder

Thunder is the sound created by a sudden discharge of electricity in the air. Like a giant electric shock in the sky, this explosion causes both thunder and lightning. Because light travels much faster than sound, lightning is often seen before or without thunder.
This means that we can estimate how far away lightning is by counting the delay between the light and the sound. The sound travels about 1.6 km every 5 seconds but is hard to hear if it's more than 24 km (15 mi) away. [AM] {GC} {WW}