Title:	Location	K-4	5-8	9-12	Description	Discipline
Middle Ear	SoundGarden	-	X	X	How is sound transformed so we can hear it?

TIP: you will need to use both a set of stereo headphones and the speakers on your multimedia computer to properly hear these effects. Make sure the volume isn't too loud!

Listen to this ...

Materials Needed:

• [ If you already completed the eardrum activity, you can use the same tube, balloon, and rubber band! ]
• 12 inch (or larger) cardboard tube
• balloon
• rubber band
• light cardboard sheet
• glue
• roll of tape
• a pair of scissors

To Do:

1. [ Skip to step #3 if you already created an eardrum ]
2. Cut a piece of balloon large enough to fit over one end of the tube.
3. Use a rubber band to secure the balloon to the tube.
4. Cut out the ossicles based on the pattern in the image above.
5. Carefully tape them onto the center of the balloon.
6. Talk into the tube and feel the ossicles at the end with your fingers.
7. Try making different sounds, like singing, humming, a wave hitting the beach, etc.
8. Now, say the words "dooby dooby doo" then say the words "when I grow up I'm going to be the first person to create a real anti-gravity generator."
9. Compare the way the ossicles vibrate. How is it different or the same?
10. What other experiments can you think of? Try them!

Your middle ear contains three tiny bones called the ossicles. They work together to transfer an exact replica of the sound energy gathered from your outer ear (air waves) to your inner ear where is finally is sent to your brain.

The first bone is called the hammer. It sits on top of your ear drum. As the ear drum vibrates it pushes the hammer.

The second bone is called the anvil. As the hammer moves, so does the anvil.

The third bone is called the stirrup. The anvil causes the stirrup to move. The stirrup vibrates on the oval window transfering an exact replica of the sound to your inner ear.

The process changes sound energy from mechanical energy into pressure waves in the inner ear. This is the main purpose of your middle ear.

The stirrup is the smallest bone in your body. What other small bones can you identify in your body?

Imagine that you are an air wave, created by a flute. Close your eyes and imagine what it would feel like to leave the flute, strike you ear, and vibrate through the eardrum ossicles, into your inner ear. What does it feel like to change forms, from air waves into mechanical waves on the ear drum and ossicles?

Strike a tuning fork and place it on your forehead. Can you hear it? Why? How is your ear connected to your skull?