Silent Bell

What you need

• Glass bottle
• Pipe cleaner
• Small bell
• Wine saver pump and stopper

Instructions

1. Attach one end of the pipe cleaner to the bell. Attach the other end to the stopper so that it can still form a good seal with the bottle
2. Put the stopper in the bottle, making sure that the bell doesn’t hit the side of the bottle when you shake it. You should be able to hear the bell
3. Use the wine saver pump to take as much air out of the bottle as you can. Then shake the bottle again

Results and Explanation

You can’t hear the bell as you have created a partial vacuum inside the bottle. Without the air in the bottle, the sound is unable to travel from the bell to your ear.

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.