Part 90

This is one of the old puzzling questions which many a high-school student has had to struggle with to the great amusement of the teacher who asks for the information and such other scholars who have already had the experience of trying to solve it.

To get at the right answer you have merely to ask one other question. If the air does not revolve with the earth, why can’t I go up in a balloon at New York, and stay up long enough for the earth to revolve on its axis beneath me, and come down again when the city of San Francisco appears under the balloon, which should be in about four hours? If that were possible, travel would be both rapid and comfortable, for then we could sit quietly in a balloon while the earth traveling beneath us would get all the bumps.

No, the atmosphere surrounding the earth moves right along with the earth on its axis. If it were not so, the earth would probably burn up--at least no living thing could remain on it--since the friction of the surface of the air against the surface of the earth would develop such a heat that nothing could live in it.

Why Does Oiling the Axle Make the Wheel Turn More Easily?

If you look at what appears to be a perfectly smooth axle on a bicycle or motor car through a powerful magnifying glass, you will find that the surface of the axle is not smooth at all, as you may have thought, but covered with what appear to be quite large bumps or irregularities in the surface. If you were to examine the inside of the hub of the wheel in the same way, you would find that it also is like that. Now, when you attempt to turn a wheel on the axle without oil, these little irregularities or bumps grind against each other, producing what we call friction. As friction develops heat, the metal of the axle and the hub expand and the wheel gets stuck.

What Made the Mountains?

There is no question but that at one time the surface of the earth was smooth, i. e., there were no big hills and no deep valleys. That was before the mountains were made. The earth was a hot molten mass that began to cool off from the outside inward. It is still a hot molten mass inside today. The outside crust became cooler and cooler and the crust became deeper and deeper all the time. Then when there would be an eruption of the red-hot mass inside, the earth’s crust would be bulged out in some places and sucked in in others and would stay that way. The bulged out place became a range of mountains and the sucked in place became a valley. This process went on happening over and over again until the crust of the earth became firmly set. Volcanos caused some of these eruptions, as also did earthquakes. There are today gradual changes occurring which to a certain extent change the outside surface of the earth, and it is possible that new mountain ranges will be produced in this way.

What Makes the Sea Roar?

The roar of the sea is a movement of the sea which causes the same kind of air waves or sound waves that you make when you shout, excepting that, of course, the vibrations do not occur so quickly in the sea and, therefore, the sound produced is a low sound. It is no different in any sense than the same noise would be if the same air waves could be produced on the land away from the water.

Why Is Fire Hot?

When a fire is lighted it throws off what we call heat rays or waves. These waves are very much like the waves of light which come from a light or fire or the air waves which produce sounds. The rays of light and heat which come from the sun are like the rays of light and heat from a fire. Heat is of two kinds--heat proper which is resident in the body, and radiant heat which is the kind which comes to us from the sun or from a fire. This radiant heat is not heat at all, but a form of wave motion thrown out by the vibrations in the ether. The heat we feel is the sensation produced upon our skins when it comes in contact with the waves created by the fire. Heat was formerly thought to be an actual substance, but we know now that radiant heat is known to be the energy of heat transferred to the ether which fills all of space and is in all bodies also. The hot body which sets the particles of either in vibration and this vibrating motion in the form of waves travels in all directions. When these vibrations strike against our skin they produce a heat sensation; striking other objects these vibrations may produce instead of a heat sensation, either chemical action or luminosity. This is determined by the length of the vibratory rays in each case.

When I Throw a Ball Into the Air While Walking, Why Does It Follow Me?

When you throw a ball into the air while moving your body forward or backward, either slowly or fast, the ball partakes of two motions--the one upward and the forward or backward motion of your body. The ball possessed the motion of your body before it left your hand to go up into the air because your body was moving before you threw it up, and the ball was a part of you at the time.

If you are moving forward up to the time you throw the ball into the air and stop as soon as you let go of the ball, it will fall at some distance from you. Also if you throw the ball up from a standing position and move forward as soon as the ball leaves your hand the ball will fall behind you, provided you actually threw it straight up.

Of course, you know that the earth is moving many miles per hour on its axis and that when you throw a ball straight into the air from a standing position, the earth and yourself as well as the ball move with the earth a long distance before the ball comes down again. The relative position is, however, the same. We get our sense of motion by a comparison with other objects. If you are in a train that is moving swiftly and another train goes by in the opposite direction moving just as fast, you seem to be going twice as fast as you really are. If the train on the other track, however, is going at the same rate of speed and in the same direction as you are, you will appear to be standing still.

Going back to the ball again, you will find that it always partakes of the motion of the body holding it in addition to the motion given when it is thrown up.

What Good Are the Lines On the Palms of Our Hands?

It cannot be said that the lines on the palms of our hands are of any great service to us. Indeed it is doubtful if they are of any value in themselves, outside of the possible aid they may be in helping us to determine the character of the surface of things which we grasp or touch. It is possible that they aid in some slight degree in this way. There is little doubt, however, that they are a result of the work the hands are constantly called upon to do rather than contrived for any particular service. The habitual tendency of the fingers in grasping and holding things throws the skin of the palms into creases which through frequent repetition make the lines of the palms permanent in several instances.

The peculiarities of these lines or creases in various individuals as to details and length and variations is the chief basis of the so-called science of palmistry.

What Makes Things Whirl Round When I Am Dizzy?

The medical term that describes this condition of turning or whirling is vertigo, which means in simple language “to turn.” There are two kinds of dizziness--one where the objects about us seem to be turning round and round and the other where the person who is dizzy seems to himself to be turning round and round.

One cause of this is due to the fact that when you are dizzy the eyes are not in complete control of the brain and the eyes moving independently of each other look in different directions and produce this turning effect on the brain, since each eye then sends a different impression to the brain instantly.

The principal cause of the sense of dizziness is, however, the little organ which gives us our power to balance and which is located near the ears. Sometimes this organ becomes diseased and people affected in this way are almost continually dizzy. Whenever this organ of balance is disturbed we lose our idea of balance and the turning sensation occurs.

It is easy to make yourself dizzy. All you do is to turn round a few times in the same direction and stop. In doing this you disturb the little organ of balance and things begin to turn apparently before your eyes. If you turn the other way you right matters again or if you just stand still matters will right themselves. There is no great harm in making yourself dizzy and very little fun.

Why Are the Complexions of Some People Light and Others Dark?

This difference in the complexions of people is due to the varying amounts of pigment or coloring material in the cells of which the skins of all animals is made up. Very light people have very little pigment; very dark people, those with dark eyes and black hair, have a great deal of this coloring material in their cells. A great many people are neither light or very dark. They have less than the dark-complexioned people and more than the light-complexioned people. When the hair turns gray it is because the pigment has disappeared. As this is due to the loss of this coloring material, dark-complexioned people turn gray sooner than light-complexioned people. The structure of the skin showing how these cells are made in layers can be seen by examining the skin with a microscope.

What Makes Me Tired?

Men were wrong for a long time in their conclusions as to what produced the tired feeling in us.