Question

An empty plastic bottle is sealed in a cool room and then moved to a very hot room. What can best be stated about the air pressure inside the bottle when the bottle reaches room temperature? It is lower than the pressure on the outside of the bottle. It is higher than the pressure on the outside of the bottle. It is the same as the pressure on the outside of the bottle. It exerts twice the force per unit area as the air pressure outside the bottle.

Answer 1

A fast moving stream of air has a lower air pressure than a slower air stream.  As the stream of air moved over the top of the paper, the air pressure over the paper dropped. The air pressure underneath the paper stayed the same.  The greater air pressure underneath lifted the paper strip and it rose. The idea that a moving air stream has lower air pressure than air that is not moving is called “Bernoulli’s Principle”.

The force of the moving air underneath the balloon was enough to hold it up.  The weight added by the paper clip prevents the balloon from going too high.  But that is only part of the story.  The balloon stays inside the moving stream of air because the pressure inside is the air stream is lower than the still air around it. As the balloon moves toward the still air outside of the air stream, the higher pressure of the still air forces the balloon back into the lower pressure of the air stream.  Bernoulli’s Principle at work again!

Answer 2

Answer:

It is higher than the pressure on the outside of the bottle.

Explanation:

After the sealed bottle is moved from a cool room to a very hot room, the temperature of the inside gas increase. Gay-Lussac's law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas, when the volume is kept constant. Therefore, the pressure in the bottle increase.