Bill James, age 12, of Peterborough, Ont., for his question:

Does sound travel faster than light?

Let's have a race between light and sound. This happens every time there is a thunderstorm. The turbulent storm cloud is a storehouse of tremendous electric charge. From time to time, the electric charge is discharged with a fiery flash of lightning. The searing heat cuts a path through the heavy moist air of the cloud, perhaps several times in a fraction of a second.

In the path of the lightning, the air is heated and, when air is heated, it expands. This strip of heated air cannot expand fast enough because it is hammered by a lazy cloud. So it explodes with a clap of thunder. The light from the lightning and the sound of the thunder are off to the races in the same split second.

The flash of lightning reaches your eyes before the sound of the thunder reaches your ears. This means, of course, that light travels faster than sound. In fact, light travels so fast that you see the lightning when it happens, whether the storm is one mile or ten miles away. The sound of the thunder lags along behind, The longer the race, the later it arrives. For sound travels through the stormy air at about one mile in five seconds. Count off the seconds between when you see the lightning and when you hear the thunder. Divide the number of seconds by five and you have a good idea how many miles the storm is away from you.

Sound is vibration and it must travel through particles of matter. When the particles of a substance are densely packed together, sound travels faster. It is a slow poke traveling through the air. Through water it can speed up to almost one mile a second and through dense steel it can speed along at three miles a second.

The higher the temperature of a substance, the faster sound can travel through it. But it cannot travel where there are no particles to carry it. There is no sound in a vacuum. You could not hear a conversation on the moon, except by radio, for the moon has no atmosphere to carry the sound.

Light travels under its own power with its own pulsing energy. It zings out in all directions from a star or from a candle. It keeps traveling at its own fantastic speed across the vast emptiness of space. This fantastic speed is about 186,000 miles a second  roughly six million, million miles in a year.

The earths atmosphere slows down the speed of light some, but not much. It still rushes towards our eyes at a speed which could whisk around the equator seven and a half times in a single second. At this speed, there is no delay between the flash of lightning and when it reaches your eyes. In fact, it gets there faster than the eye can flash the information to the brain.