What you need:
Glass jar with a lid and a wide rim, water, white chalk, round balloon, scissors and a thick rubber band.
What you do:
1. Pour a little water into the jar and screw on the lid tightly. Leave it for 20 minutes.
2. Crush the chalk into a fine powder. 3. Cut the neck off the balloon.
4. Open the jar and put in the chalk powder.
5. Quickly cover the jar with the piece of balloon by stretching it over the rim.
6. Put a rubber band around the neck of the jar to keep the balloon stretched tight.
7. Press the balloon down with your fist to compress the air. Hold it like this for 30 seconds. 8. Rip off the balloon.
What you see
A cloud has formed inside the bottle!
Why it happens
When you compress the air in the jar, it becomes warmer. It absorbs more evaporated water or water vapour.
When you take away the balloon cover, the air becomes cooler. Cool air can’t hold much water vapour. Some of it condenses on the chalk dust and makes a cloud.
Picture Credit : Google
