Turn Up the Sound

Some sounds you hear are soft and some are very loud. In science class you have been investigating how energy—including sound—travels in waves. In this activity, you can observe how sounds travel through different forms of matter.

Materials

A fork hanging from a string that is tied to a pencil. The string is vibrating.

Procedure

With the help of a family member, cut a 12-inch piece of string. Tie one end of the string to the middle of the metal fork. Tie the other end of the string to the pencil. Hold the pencil with one hand so that the fork hangs freely. Use the spoon to tap the fork. Now carefully place the eraser of the pencil so that it just barely touches the top of the ridge of your outer ear. Have your family member strike the fork once again with the spoon.

Results

Talk with your family member about the results of the activity. How loud was the sound you heard when you tapped the fork without placing the pencil to your ear? What was its pitch? For how long did the sound last? What was the volume, the pitch, and the duration of the sound when you placed the pencil on your ear?