357.WHAT IS THE UNITED NATIONS?
In these times of world tension, we hear a great deal about the United Nations. What is it? Why was it established? What is it supposed to do? We can give only a brief description of the United Nations here, but here are some things you should know about it.
The United Nations is an organization of governments. It was set up to prevent war and to build a better world for all by dealing with problems which can best be solved through international action. The UN constitution, known as the Charter, was signed at San Francisco on June 26, 1945, by representatives of 50 nations.
356.WHO INVENTED THE MICROSCOPE?
The word microscope is a combination of two Greek words, mikros, or “small,” and skopos, or “watcher.” So microscope is a “watcher of the small!” It is an instrument used to see tiny things which are invisible to the naked eye closer it is brought to the human eye.
But when it is nearer than 25 centimeters, it is not clear. It is said to be out of focus. Now if a simple convex lens is placed between the eye and the object, the object can be brought nearer than 25 centimeters and still be in focus.
355.WHAT IS USED IN MAKING GLASS?
We may think of glass as being produced by the mixture of some very special chemicals in a very special way, a sort of miracle of chemistry. But actually, glass is made by a rather simple process using quite ordinary materials. Glass is a substance made by “fusing”(melting together) certain materials, and then cooling the mixture so that the atoms arrange themselves in an unorganized pattern. What materials? Well, about 95 per cent of the raw materials in the earth could be used in making glass! The most important materials used in making glass, however, are: sand (silica), soda, limestone, borax, boric acid, magnesium oxide, and lead oxide.
