Part 14

This occurs simply because lightning or light travels so much more quickly than sound. Light travels at the rate of 186,000 miles per second, and sound travels only at the rate of 1090 feet per second when the temperature is at 32 degrees. Now, the thunder and lightning come at the same time and place in the air, but the light travels so much faster that you see the lightning often quite some seconds before you hear the thunder. In fact, you can tell quite accurately how far away from you the flash of lightning and clap of thunder are by taking a watch and noting the number of seconds which elapse between the flash of the lightning and the time when you hear the roll of the thunder. If as much as five seconds elapse you can figure that it was about a mile away from you, since sound travels only about 1100 feet per second and there are 5280 feet in a mile. When the thunder and lightning come close together you may know that it is near by, and when they come at the same time you may be sure it is very close. When, therefore, you see the lightning and then have to wait several seconds for the noise of the thunder, you may rest easy about the lightning hurting you, because you know then it is too far away to harm you, and when it is so close that the lightning and thunder come simultaneously, there is no use being afraid, because if you were to be struck you would have been struck at the same instant or before you would have had time to notice that the lightning and thunder come together.

How Big Is the Sun?

It is very difficult to gain a clear idea of how very large the sun really is. We know from the scientists who have measured it with their accurate measuring instruments that it is 865,000 miles through it, and that at its largest part it is 2,722,000 miles around. Now, you can see why I said it is very difficult to get a clear conception of the sun’s size. A mile is quite a long distance to walk on a hot day. Now, the earth is 8000 miles through. If there were a tunnel right through the earth, like the subway, and you started to walk it, it would take you 83¹⁄₃ days if you walked day and night without stopping to rest or eat, if you kept going at the rate of four miles every hour. This would be a long, hot walk, for, of course, the inside of the earth is hot, as we have already learned. It would take an automobile, going at the rate of 40 miles an hour night and day, about nine days to make the trip through such a subway from one side of the earth to the other. That makes it look like a pretty big old earth, doesn’t it? But let us see what would happen if we started to do the same thing on the sun. The sun is 865,000 miles through. If you were to walk through a similar tunnel on the sun at four miles per hour it would take you 20 years, not counting the stops, and an automobile going 40 miles an hour day and night would take two years and a half to make the trip one way.

The sun is ninety million miles from the earth and an automobile travelling at the rate of forty miles per hour day and night on a straight road, without stopping, would be 257 years in getting there.

When we stop to think of how big the bulk of the sun is it is altogether beyond us. We have a general idea that our earth is a pretty large affair as worlds go, and yet we cannot conceive how much the bulk of the earth amounts to. Still, the sun is so large that it could contain a million worlds like our own.

How Hot Is the Sun?

We think the sun is pretty hot in summer when the thermometer goes up to 90 degrees in the shade or out. We begin to get sunburned long before it reaches that high. But right on the sun’s surface it is between 10,000 and 15,000 degrees hot. That is, of course, a degree of heat which we cannot conceive. How much hotter still it is on the inside of the sun we don’t as yet know. It must be awfully hot there.

Why Is It Warm in Summer?

It is warm in summer because at that season of the year the heat rays of the sun strike our part of the earth through less air. The blanket of air which surrounds the earth is very much in comparison as to thickness like the peeling of an orange and surrounds the earth in just the same way. If you stick a pin straight into an unpeeled orange you only have to stick it in a little way before you reach the juicy part of the orange, but if you stick the pin in at an angle the pin will travel a much longer ways through pure peeling before it strikes the juicy part. Now, then, in summer the rays of the sun come down to us straight through the peeling of air, and less of the heat is lost by contact with the air, and that makes it warmer in summer. The explanation also accounts for your next question.

Why Is It Cold in Winter?

In winter the heat rays of the sun strike at our part of the earth at the angle at which you stick the pin into the orange when you wish to make it travel through the most peeling. In winter the rays strike the earth at such an angle that a great deal of the heat is lost in travelling through the air, because they have to come through so much more of the air. Of course, the sun’s rays strike some part of the earth straight down through the peeling of air at all times, and at the equator this occurs all the year round, so it is always summer there, while at the North and South Poles the rays always strike the earth at the greatest possible angle, and it is always very cold winter there. In between, when it is neither hot nor cold, we have spring and fall, due to the fact that the rays come down at an angle, but not so great an angle.

Why Have We Five Fingers on Each Hand and Five Toes on Each Foot?

All animals, it seems, from a study of nature were started with ten fingers and ten toes, the fingers originally having been the toes of the fore legs. In a good many cases the environment in which animals have lived has caused a change in the formation of the ends of the limbs as well as in the limbs themselves. The horse, for instance, has developed into a one toe or one finger animal, while a cow is a two finger animal. The hen has only three toes on each foot and a part of another. But if we go back into the history and examine how the horses’ foot used to look we will find that he originally had five toes. The same is true of the cow and also the hen. Something happened to cause the change, for the rule of five fingers and five toes on the end of each limb has been universal. If you examine a chicken in a shell just before it is ready to come out, you can distinctly count five toes on each foot and at the ends of the wings you will see five little points, which under other conditions would develop into fingers, perhaps. Some of these toes of the new-born chicken do not develop. It can be accepted as a rule that creatures were intended in the original plan to have five fingers on each hand and five toes on each foot, making our count of tens, which is the world’s basis for counting, and has always been.

Why Do We Have Finger Nails?

Finger nails and toe nails are only another phase of the development of man from the animal that originally walked on four feet. Animals that walk on all fours use the finger and toe coverings which in man is the nail, to scratch in the ground, to attack enemies, and to climb with, and our nails of the present day are what the development of man into a civilized being has changed them to. At that, there are still uses for finger nails and toe nails, or man in his changing to a higher plane would have found a way to develop away from them. They are useful to-day in making our fingers and toes firm at the end, and enable us to pick up things more easily. The time may come when man will have neither finger nails nor toe nails.

Why Are Our Fingers of Different Lengths?

There is no known reason why our fingers should be of different lengths to-day; in fact, it is thought by some people that the hand would be stronger if the fingers were all of the same length. Certainly, however, the hands would not then be so beautiful, and it might not be so useful. The human hand to-day is perhaps the most versatile thing in the world. You can do more things with the hand than with any other thing in the world. The probability is that the shape of the hand to-day and the length of the fingers are the result of the different things the human being has called upon the hand to do during man’s development up to the present time.

We must go back to the time, however, when man walked on fours, for that is probably the real explanation. Originally man’s fingers were of different lengths because all four-footed animals had the same peculiarities. The shape and length of the toes and their arrangement were the ideal arrangement for giving the proper balance and support to the body, and in moving about and in climbing produced the best toe hold.

Why Does It Hurt When I Cut My Finger?

It hurts when you cut your finger, or, rather, where you cut it, because the place you have cut is exposed to the oxygen in the air, and as soon as it is so exposed a chemical action begins to take place, just as when you cut an apple and lay it aside you come back and find the cut surface all turned brown. If the apple could feel it would hurt also, because the chemical action is much the same. The apple has a skin which protects its inside from the oxygen in the air, and you have also a skin which protects you from the oxygen as long as it is unbroken.

What happens, of course, is this: When you cut your finger you sever the tiny little veins and nerves which are in your finger. They are spread all over your body like a net-work under the skin, close to the surface in most places. The nerves when cut send a quick message to the brain, with which they are connected, telling that they are damaged, and the brain calls on the heart and other functions to get busy and repair the damage along the line. There may be some hurt while this process of repairing is going on, but the principal part of your hurt, outside of what we call your feelings, is due to the fact that the inside of you is thus exposed to the chemical action of the air. Then I can hear you say next:

Why Don’t My Hair Hurt When It Is Being Cut?

It does not hurt to cut anything that has no nerves. There are no nerves in the hair which the barber cuts. If he pulls out a hair it hurts, because the root of the hair has nerves, which telegraph notice of the damage to the brain. When a dentist takes out or kills the nerve in your tooth you cannot have any more toothache in that tooth, because there is no nerve there to send the message to the brain. You can cut your finger nails without feeling pain, because they have no nerves at the ends, but underneath, where they join the skin of the finger, there are a great many nerves, and it hurts very much to bruise the nails at that location.

Of What Use Is My Hair?

~WHY WE HAVE HAIR~

Your hair is a relic of the days when the entire body was covered with hair, just like some animals to-day, to protect the body from the heat, cold and wet. Man has, however, for so long a time worn clothes over most of his body that the need of the hair to protect him from these elements has all but disappeared, and so also has the hair, excepting in such places as the top of the head and face and other exposed parts. If you were to go out into the woods without clothes and live a long time your body would probably again become covered with hairs. The time is coming, however, it is believed, when human beings will have no hair at all on their bodies. You have hair on your head, but if you were to wear a hat or cap all the time you would soon be bald. Hair is of no use to us to-day excepting to adorn our bodies and add to our appearance. This it seems to do to-day, probably because we are accustomed to seeing it, and will make no difference in our looks relatively if the time comes when we have no hair at all.

Why Does My Hair Stand On End When I Am Frightened?

It does this under certain conditions, because there is a little muscle down at the root of each hair that will make each hair stand up straight when this muscle pulls a certain way. It is difficult to say just how these muscles are caused to act in this way when we are frightened. We know that when thoroughly frightened our hair will sometimes stand straight up, and we know that it is this muscle at the root of each hair that makes it possible, but why it is that a big scare will make this muscle act this way we do not as yet know.

What Makes Some People Bald?

The chief cause of baldness is the lack of care of the hair. It is as necessary for the roots of the hair to have a free circulation of the blood and that the hair itself should have plenty of air as it is necessary for the brain to have a good circulation. A great many men become bald through wearing their hats most of the time. The hat pulled down tight over the head presses against the scalp and interferes with the circulation of the blood in the scalp. Then, also, many hats do not have any means of ventilation, and that keeps the pure air away from the hair. The hair then becomes sick and dies, just as flowers wilt if you keep them away from the air. You will notice that women do not become bald so easily. One reason is that even when the women wear large hats, as they often do, there is plenty of room for the air to circulate through the hair, even when the hat is on, and women’s hats are not pulled down tightly on the scalp. Therefore, they do not press on the arteries and veins in the scalp and interfere with the circulation of the blood. Another reason why women do not become bald is that the hair of women has long been their “crowning glory”; a man likes to see a fine head of hair on a woman, and as women have long tried to please men in every possible way, they take better care of their hair than men do, because they like to have the men consider it beautiful.

What Makes Some Things in the Same Room Colder than Others?

The objects in a room which has been kept at a given even temperature of heat will be all the same temperature, because heat spreads from one thing to another equally.

Still, if you put your hands on various objects in such a room some of them will feel colder than others. You touch the tiling of the fireplace and that will feel cool to you. On the other hand, the upholstered furniture will feel quite warm. The piano keys feel cool, while the wood of the piano and case is warm. The difference is due to the fact that heat or cold will run through some objects more quickly than through others. It will run through the tiling on the hearth and the piano keys more quickly than through the upholstering on the furniture or the wood of the piano case. When you touch a thing with your finger you supply some of the heat of your body to the object through your finger. If the object is the tiling on the hearth or the keys of the piano the heat runs through it quickly and you get a cold impression in your finger. On the other hand, if you touch the upholstery on the furniture, through which the heat runs slowly, you get a warm feeling for the very same reason. Thus, anything which carries the heat away from our contact quickly we call a cold feeling object, and if the object touched does not carry the heat away so quickly we call it a warm feeling object.

Why Does the Hair Grow After the Body Stops Growing?

The hair on our bodies is one of the things that is continually wearing or falling away, and since, like the skin, it is necessary to protect certain portions of the body, the hair keeps on growing long after the grown up period has arrived. The skin is a very necessary protection of the whole body, but is constantly being worn away, and is all the time being replaced. Your hair falls out when it is not healthy. Unless proper care is given to it, it will fall out and not grow in again, and then we become bald.

Will People All Be Bald Sometime?

There is a theory that before many years have passed human beings will lose all of the hairs which now grow on different parts of their bodies, due to the fact that we wear so much clothing and keep so much of our bodies away from the sunlight. If that time comes we shall have a hairless race of men and women.

THE STORY IN A LUMP OF SUGAR