Blowing Sounds

Sound

Things You Will Need
• Empty plastic or glass bottle
• Water

   

   

   

Do This

1. Put the top edge of the empty bottle to your lower lip and blow lightly across the top.
2. Observe the sound that is made.
3. Pour a little water into the bottle and dry off the bottle lip.
4. Blow again and observe the sound that is made.
5. Add a little more water and dry the bottle lip.
6. Blow again and observe the sound that is made.

What Should Have Happened

The more water that was added, the higher the sound should have been. When you blow across the top of the bottle, you are vibrating the air in the bottle. Adding water to the bottle leaves less room for air. The less air there is in the bottle, the faster the air vibrates and the higher the pitch. The more air in the bottle, the slower the air vibrates and the lower the pitch. This is the same way musical instruments called wind instruments produce sounds.