April 30, 2004

A sound is made by very small, fast movements of the air. The sound waves pass through you ear to your eardrum, and the waves make your eardrum vibrate. Messages about the vibrations go up to your brain, and you hear a sound. For example, when you clap, the air around your hands vibrates and forms waves.
In the same way, musical instruments make sounds by vibration. A stringed instrument, like a guitar, makes vibrations when you pluck the strings. Percussion instruments, like a xylophone, make vibrations when you hit them with something, like a stick. Wind instruments like a flute make vibrations through the holes on the top. When the player blows into the flute, they cover some of the holes with their fingers, and a sound comes out.

Voices: When you use your voice, you make vibrations. If you put your hand on your throat and hum, you can feel the vibrations made by your vocal chords. When air passes through your vocal chords, they vibrate and make a sound.

What is Volume? The volume of a sound depends on the energy put in to it. For example, if you have a guitar, the harder you pluck the strings, the more the strings vibrate. The amount of vibration is called the amplitude. The bigger vibrations will have louder sounds than the smaller vibrations.

High and Low Sounds: Not only can vibrations make loud and quiet, they can also make noises sound high, or low. Pitch is how high or how low a sound can be. The pitch of a note depends on how fast a sound wave vibrates. The speed of these vibrations is called frequency. Fast vibrating sounds make high-pitched noises, and slow vibrating sounds make low-pitched noises.

I did an experiment that I would like to share in my paper: Toilet paper tube kazoo what you need: toilet paper tube (Or a paper towel tube)
Wax paper,
rubber band
scissors

Cut out a square of the wax paper that is bigger than the hole at the ends of the tube. Cover one end of the tube with the wax paper and put a rubber band over it, to hold it down. Cut a SMALL hole out of the top, right by the wax papered end. Sing into it, and listen to the music! (do not cover the hole, because it won’t work if you do.) The buzzing sound that the kazoo makes is caused when you blow air or sing into it. The air from your mouth bounces off of the wax paper and out of the hole. If you cover the hole, the vibrating of the wax can’t be heard because the sound waves that it is giving off can’t escape.

This report was very fun to do! It was pretty cool to learn so much about sound, because it didn’t seem like a very interesting subject, but I was fascinated with sound waves. I hope that this report helps you to learn more about sound.