WHY DO THINGS HAPPEN?

Evening Star, Issue 21689, 7 April 1934, Page 5

WHY DO THINGS HAPPEN?

Who Invented Fire? This is one of the questions that go right to the very beginning of things. Fires in forest and prairie occur naturally, and man first learned to use fire, then how to keep it going, and only after long experience of its advantages how to make it. This he perhaps did as’the bushmen and other very primitive peoples do to-day, by twirling between the palms of the hands a very dry stick resting on another piece of wood surrounded by tinder. By long and rapid, twirling the stick generates so much heat by friction that the tinder glows and can be blown into flame. How Do Aeroplanes Keep Up in the Air?

If you know why a kite rises and flies in the wind you know why an aeroplane does, too. for it is really only a kite with an engine to make it keep flying by providing it with its own wind. When yon fly a kite the air (or wind) strikes against its under-surface, which you are holding on the slant by the string. As the air pushes against the slanting surface the easiest thing fop the kite to do is to go up and let the air go Tinder it. You cannot fly a kite unless the wind is blowing or you make the air move by running along, pulling the kite through the air. So the aeroplane uses a propeller like a shTp’s screw in the water t.o make itself move. In order that the aeroplane can be guided up and down and turn, it is provided with a tail plane and rudder." Who Were the Minute Men? In the American War of Independence against Great Britain the various American colonies organised militia forces. Many of the men so raised agreed that they would be ready to march at a minute’s notice, and they were therefore called Minute Men. Fifty of them were in the skirmish at Lexington which opened the war in April, 1775.

Why Do People Seldom Live To Be Over 100? All machines have a limited life. They wear out as they are used. We can repair them, but the time comes when they are too far worn to be repaired any more. The human machine, the body, is always repairing, building itself up. In youth the building up is stronger than the breaking down, but as we get older the process is gradually reversed, and we then say that we see signs of age. The long-lived people, those whose bodies wear out so slowly that they reach 100, or very occasionally a little more, seem to be those who come from long-lived families —that is, they inherit a tendency' to live longer than other people —and those who live simple healthy lives free from worry. Why Do Some Flowers Open at Night and Others in the Day? Night-opening flowers are almost rare exceptions. Most are open during the day for light and pollination by insects, and closed at night for protection against heavy dews and frosts. Night flowers, like the evening primrose, tobacco plant, and night-scented stock, are fertilised by night-flying moths and are nearly always white or light coloured and powerfully scented, both being devices to attract insects in the dusk and dark. When the light diminishes and the temperature changes with the approach of night the insides of the petals of the flowers expand, so that they are forced outward and the flowers are thus opened. Flowers also seem to go by the clock, it has been noticed that the opening of some flowers is followed twelve hours later by closing, and this rhythm of opening and closing continues for some days, even if the plants are kept in darkness. Thus night-flowering plants, like daytime ones, may have a habit of this sort.