Janet Titko, age 11, of St. Catharines, Ont., Canada, for her question:

Where does sound go to?

Sound is vibration, which is a form of pulsing energy. It starts up when you beat a drum or shout, Hello. From the starting point, the Sound travels out in all directions. Through ordinary air it travels a mile in about five seconds, but, as it travels, the energy that produces the sound is absorbed by the land and the air.  As it travel it gets weaker and weaker until there is no sound at all.

In a thunderstorm, the lightning and the thunder happen at the same moment. The thunder is loudest when the storm is right overhead. As the roaring sound travels, it loses its energy and gets fainter. Heat lightning comes from a storm so far away that the thunder has no energy left to make a sound when it reaches your ears.