Sound travels by sound waves that are much like the waves you see in water. Sound waves can be strong and big, like a stormy sea, or they can be weak, as when the sea is flat and calm. When a jet plane flies directly overhead, the sound waves are strong and we hear a loud sound. When somebody whispers softly, the sound waves are small and weak.
Sound waves can travel through air or water or even through solid things such as doors and walls. When you hear your mother and dad talking in another room through a closed door, you are hearing the sound waves of their voices passing through your door. And when a friend yells from the out¬side and asks you to come out and play, you may be hearing the sound waves right through the walls of your house.
Hearing takes place when sound waves enter the ear and strike against the eardrum, causing it to vibrate that’s moving back and forth quickly, or quivering, almost like what happens when you shake a bowl of Jello.
When the eardrum vibrates it causes three little bones just behind the eardrum to vibrate too. The vibration of these three bones-the malleus, incus, and strapes-transmits a signal to the inner ear. The inner ear is filled with a fluid, and this fluid passes the vibrations along to the nerve of hearing, called the acoustic nerve. The acoustic nerve picks up the signal from the inner ear and sends it on to the brain. The brain then interprets the signals it receives sound and, within the flash of a second, can say, “I hear Mom’s voice” or “that’s Dad speaking” or “that’s the baby crying” or “that’s thunder” or “that’s the music of my favorite song”.
It is really amazing how we hear! And all it takes is the time to blink an eye for anyone to hear something. The second someone makes sound waves by talking, your ear picks up the waves, sends the vibrations to your eardrum, then to the three little bones, then to the inner-ear fluid, then to the nerve of hearing, and finally to that amazing brain inside your skull.
Sound waves are transmitted through the ear canal and the middle ear to nerves in the inner ear, which send Impulses to the brain. The various parts of the ear are very delicate and can be damaged by repeated loud noises.
To keep our hearing at its very best, there are certain rules to follow:
1. Never stick anything into your ear or into anyone else’s ear. The eardrum may be hurt, and that could interfere with hearing. However, if an insect accidentally flies into your ear, or if you accidentally lose something in your ear, don’t worry, because it is easy for a doctor to remove it.
2. Always tell a grown-up when you have a pain in your ear. It may be necessary for you to take med¬icine to clear up an ear problem.
3. Always tell someone if you don’t hear as well as you usually do. You may need to have the wax cleaned out of your ears. Or, if you have an ear infection, you may need medicine to clear it up.
4. Don’t shout into another person’s ear. Remember, very strong sound waves can do damage.
5. Get into the habit of playing your radio or television set softly. It has been found that people who work in places where there is loud noise all the time don’t hear as well as others.
6. When people talk to you, look right at them. You can always hear better when you look at the person who is speaking to you. And that way he won’t have to speak so loudly.
7. Don’t listen to the radio or to television while you are reading a book or magazine. If you want to be sure to understand what you are reading, concentrate on it. If you want to hear the radio or television program properly, then concentrate on it. You can’t do both well at the same time.