Procedure
Heating a gas
1. Add hot water to a wide cup until it is
about 1/3 full.
2. Lower the open mouth of the bottle into
the cup with detergent solution as shown.
Carefully tilt and lift the bottle out so that
a film of detergent solution covers the opening of the bottle.
3. Slowly push the bottom of the bottle down into the hot water.
The lid rises and falls making a tapping sound.
Note: If you would like to show the demonstration again, you can uncover the opening and let some more
air in. Then repeat Steps 2 and 3. If the lid does not tap, check to see that the lid is positioned directly over
the opening of the bottle forming a seal.