Bottle Orchestra

What you need

• Two glass bottles
• A wooden spoon
• A jug of water
• Good ears

Instructions

1. Fill one bottle ¾ full of water and the other ¼ full of water
2. Tap both bottles and listen to the sound they make. Which one is higher pitched?
3. Now blow across the top of each bottle. Which bottle makes the higher pitched sound now?

Results and Explanation

The easier it is for the glass to vibrate when you tap it, the higher the frequency. So the bottle with less water in will sound higher pitched.
The less air there is in the bottle when you blow over it, the faster it vibrates. So the bottle with more water in will sound higher pitched.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.