One day, Bernie and Hayley were sitting out on their deck, sipping on some drinks. Bernie ran into the house, got an empty 2-liter bottle from the freezer and a quarter and returned to the deck.
"I bet you money that this quarter will move with nobody touching it", said Bernie.
Hayley thought this was a sure win, however, she lost. When Bernie placed the quarter on the mouth of the bottle, the quarter began jumping on one side and making popping sounds.
How did Hayley lose?

Since the bottle was in the freezer and a 2 litre bottle has a skinny neck, the bottle would be full of near-freezing temperature air at the time the quarter was placed on top. The quarter makes a reasonable (but probably not perfect) seal on the bottle.  As the air in the bottle warms after it leaves the freezer, the air pressure inside rises until it is just enough to lift the quarter slightly and reduce the pressure.  This burping action will repeat until the air in the bottle is sufficiently close to the outside air temperature to prevent any further such "releases".

Posted by Kenny M on 2022-09-06 07:25:59