1. Sound: How it works
Brittany York

2. How does Sound Travel from your Voice to Your Friend’s Ear?
Your Brain→ Your Vocal Folds→ Vibrations→ Your Friend’s Ear→ Your Friend’s Brain

3. Vocal folds
Vocal Folds , also called Vocal Cords, are streched across your trachea. When you speak, the folds vibrate producing sound.

4. Vibrations
When a sound is made it causes a vibration. The vibrations can travel as waves through solids, liquids, and gases.

5. Predict: Can Deaf People Feel Vibrations?
Answer: Yes, deaf people can feel vibrations sometimes better than hearing people do. Even animals that have no ears can feel vibrations.

6. Vibrations Produce Different Sounds Depending on the Size!
The size of something changes the pitch! The larger something is, the lower the sound. If something is small, the pitch will be much higher. Example: Big dogs have low scary barks while small dogs have high squeaky barks.

7. I’ll Prove it!
1. Place the popsicle stick in front of you with just a small part off the edge of your desk. 2. Push down on it to make it vibrate. You hear a high pitched sound. 3. Now, place the popsicle stick with a larger part of it off the edge of your desk. 4. Push down to make it vibrate. Now, you hear a lower pitched sound.

8. Predict: Why do Males and Females Sound different?
Answer: Males have larger vocal folds than females. Remember: The larger an object, the lower the sound!

9. Your Ear Sound reaches your ear through the canal.
Sound causes the ear drum to vibrate.
The vibrations causes the three bones in the middle ear , the hammer, anvil and stirrup to vibrate hittting the cochlea.
Inside the cochlea are tiny hairs which transmit the sound to the brain.

10. The Old Telephone Trick
Many believe that Alexander Graham Bell, himself, tried this experiment.
How it works:
Attach two cups to a string. Pull the string tight! Speak into the cup and see if your partner can hear you.

11. Does it Really Work? Let’s try it!
With a partner, create the telephone using the cups and string provided. Then speak to your partner. Speak at different levels to see if you can hear each other. Don’t forget to pull the string tight!

12. Did it work? Why?
Yes, it works! When you speak, the vibrations hits the bottom of the can. This causes the string to vibrate which then causes the bottom of the other can to vibrate the same way which produces sound!