Soundless Vacuum (Funky Physics Experiments)

You will need:

1. Empty 1-litre thick
   glass bottle
2. Matchsticks
3. Small bell
4. Tape
5. Ribbon

Do you know that sound cannot travel in space? Conduct this simple experiment to find out whether sound can actually be heard in vacuum.

INSTRUCTIONS

1. Take the small bell and attach a ribbon to it. Attach the other side of the ribbon to the inside of the cap of the glass bottle with the help of tape.
2. Screw the cap back on the bottle and shake the bottle gently. The bell should jingle and you should be able to hear it.
3. Now unscrew the cap and light 2 matchsticks. Ask an adult to help you.
4. Take the lit matchsticks and gently drop them inside the bottle.
5. Screw the cap back on tightly, and wait for the matchsticks to get extinguished.
6. Once the matchsticks go out, gently shake the bottle and you will realize that the bell will hardly be audible now.

RESULT

When the matchsticks are dropped into the bottle, they use up most of the oxygen inside the bottle since the bottle is tightly shut. This creates a sort of vacuum inside the bottle. Unlike light, sound requires some sort of medium to travel and vibrate off. With next to little oxygen left in the bottle, there is no medium for the sound to travel through, and hence the bell inside the bottle will hardly be heard.