The tube will not contain lots of air
Because the pressure is lower up in a higher elevation, there for the toothpaste expands or "Explodes" when you get up there.
It gets thinner (the pressure drops) and colder.
Air pressure decreases as you go higher.
The pressure inside the balloon will be higher because the balloon will try to get smaller and thus the balloon will ascent due to the low density of the helium inside the balloon.
The pressure is higher.
The gas pressure in the flask is lower than the atmospheric pressure when the water level is higher inside than outside the flask.
at higher altitudes the pressure of air is greater in our lungs as compare to the air pressure outside the body
There is no difference of the average local air pressure inside or outside of the headphone.
The air pressure inside the can is always higher than the air pressure outside the can. The air is compressed into the can along with the tennis balls.
If pressure is higher in the inside of the eardrum, the eardrum will pop. If pressure is higher outside the eardrum cave in.
Atmospheric pressure falls
It was packaged at a lower elevation where the air pressure is higher. As you move to a higher elevation the external air pressure decreases, but the air pressure in the bag stays the same. So the bag "blows up" like a balloon because the pressure inside it much greater than the pressure outside. Same thing happens in your ears.