Last night as I watched the passing thunderstorms, from inside my house, I wondered what is thunder.  I thought it was the sound of the lightning but I was not sure.  My husband wasn't sure either, so I came to work and found two great books about thunderstorms.

Flash, Crash, Rumble and Roll by Branley (you can find it at J551.554 BRA in the nonfiction books at the library)

and Thunderstorms by Sipiera (J551.554 SIP)

"Lightning occurs when electricity or energy, builds up inside large, dark storm clouds..."the"flow of positive and negative electricity produces lightning". -Thunderstorms

"Thunder comes after the lightning.  The lightning is very hot.  It heats the air.  The hot air expands very fast.  It makes sound waves all along the streak of lightning.  The sound waves reach you at different times.  When the first one reaches your ears, there may be a loud crash.  As more and more sound waves reach you, thunder rumbles and rolls."-Flash, Crash, Rumble and Roll

Miss Jennifer