Flash Crash Rumble and Roll Author:Franklyn M. Branley Everyone know what a thunderstorm is. Big, dark clouds form in the sky. The rainfalls fast and hard. Lightening flashes again and again, and you hear the thunder crash, rumble, and roll. But what makes a thundercloud? What is a boult of lightning? And why does thunder somtimes sound so loud? Curl up in a chair and find out not only why all... more » these things happen but how you can stay safe in the storm.« less