is made up of tiny separate molecules. But see the rainbow colors it reflects. A diamond cut in faces, catches white light rays and breaks them up in the same way. So the soap bubble would not be able to break up light rays, if it did not have millions and billions of little flat faces.
If you watch a soap bubble closely you will see it sag and gather a drop on the underside. No sooner is it in the air than the earth tries to pull it down. Because of this pull the water on the upper parts slides down the slopes. That makes it heavier below. The heaviness drags it out of its perfect sphere shape. All this time the air inside is growing cooler and is shrinking. The water-film shrinks Ito lit the air inside, and is pressed in by the outside air. When both are the same weight and temperature, the water skin makes the bubble heavier than the air it floats in, so it falls, just as an apple does. When the bubble touches the ground all the little molecules of water fall together, downward, and make one drop.
You cannot believe the glittering little fairy world is all in the soapy splash on the table, can you?
WHY IS THE OCEAN SALT?
There is no salt in fresh rain-water. River water tastes fresh, sea water salty. Yet the oceans are fed by the rivers that flow into them. Then where does the salt in the sea come from?
When rain falls on the ground it soaks into the earth. In the earth are all sorts of minerals—salt, lime, magnesia, potash, sulphur, iron and many others. These are dissolved or melted and carried along by the water. Of all the minerals in the earth salt is most easily dissolved by water. So very often, we have salt springs. Rivers are fed by springs, and all of the minerals are in river water, but not enough so you can taste them. All the time this salt and other minerals are poured into the ocean by the rivers. When the sun takes vapor up into the rain clouds it takes only the water, leaving the minerals behind, just as lime is left in a teakettle. In this way the minerals in the sea, salt and everything else, slowly becomes greater in quantity as the centuries go by. About three and a half per cent of sea water is minerals, today. That is, if you put one hundred quarts of sea water in a tank and boil it until the water is all boiled away, you will have three and a half quarts of dry salt, magnesia, lime, potash and other minerals. The greater part would be salt.
