Barbara Salter, Age 12, Of Toronto, Ont., Can., for her question:

Why do we need sleep?

young peop1e, as a rule, are never ready to go to bed when the day is done. Andy also hates to fall asleep when there are so many interesting things to be seen and done. But these notions are quite wrong. When we miss our sleep, we are in no shape to enjoy anything at all. When our eyes sag shut and our tempers get short, when we get wobbly on the legs and foggy in our heads, we may be suffering from lack of sleep. a new born baby sleeps through two thirds of his young life. An adult spends about one third of his life sleeping. Sleep is such an everyday event for all of us that you would think science can tell us all there is to know about it. But this is not so. The nature of sleep and the reasons why the body cannot get along without it are problems still waiting to be solved. But we do know what happens to people who fail to show a sensible attitude to sleep. When a student decides to work or play through half the night, his or her grades art going to be the worse for it. Lack of sleep dulls that part of the mind which thinks and reasons. Muscular action also suffers. When an athlete misses his quota. Of sleep, he loses coordination.

So the thinking part of our brains must need sleep to keep in sharp working order. The rest of the nervous system also gets out of order, which upsets the motions. A person suffering from lack of sleep is likely to be bad tempered. Since his brain is not at its best, he is sure to show poor judgment if he gets into a quarrel.

We know that lack of sleep will cause these unpleasant things to happen. We can assme, then, that we need sleep in order to refresh our minds and the nerves which control our muscles. But even the experts are not sure why this is so.

It may be that the body works overtime during its waking hours and the delicate communication systems of nerves and muscles become overcharged. They may become clogged and fatigued with accumulated waste materials. In any case, after a busy day, the body must close down operations and shut out all the information coming to it from the outside world. It must rest and refresh itself with a period of seven or eight hours of sleep.

Some people need more sleep than others, and when you grow older you must set your own rules by what seems right for you. A good test is how willing you are to wake up in the morning. If you are too dopey to enjoy breakfast in time to catch the school, bus, chances are you need more rest , and, of course, the proper time to get that extra ration of sleep is when bedtime rolls around at the end of the day.