Another visit from America's favorite science teacher Bill Nye. Today he explores the forces of our atmosphere in three experiments demonstrating how air pressure opposes gravity. First aired May 18, 1991 Copyright King 5 - Almost Live!
The frozen water molecules expand causing pressure, the water that is unfrozen is pushed out because the space it then occupies is smaller than the same amount of molecules would have if the whole bottle were thawed.
wait, if you suck all the air to create vacuum, why doesn't it crush? do they just suck enough air so that it's way less dense, but not enough for it to crush or break?
it is being crushed, but the molecular forces holding together the material, is much stronger than the pressure difference created in this lab. Also, when sucking the air out of a closed system, you can't really suck "all" of the air out. It's basically impossible to create a perfect vacuum, and so that's why when you suck the air out of a tube like in this lab, your just creating a pressure differential, between the atmosphere and the tube and not an actual true vacuum.
The joker card sticks up due to the pressure of water above it and not the pressure of air underneath! If the same experiment is repeated without water in the test tube anyone can come to that conclusion because the pressure of air still exists but the card cannot stick up.
