Why in airplanes do our ears pop?

FGOKURULES

Due to the difference in pressure from outside of the plane; from the surrounding air. As the plane goes higher air is literally sucked from inside of the plane, which is why all planes have a pressurization system to maintain cabinet pressure to a safe level on the plane. As far as your ears, think of it like this; Have you ever seen a marsh mellow expand when it is put in a jar and all the air sucked out? The ear drum is similar to the consistency of a marhmellow. Thus the increased air pressure from outside the plane expands your eardrums and POP! Aug 29 06, 9:33 PM

Gnomon

As we ascend in an aeroplane, the pressure in the cabin decreases. Our ears have air on each side of the eardrum, which is a stretched membrane similar to the top of a drum. When the air in the cabin is much less than the air inside our ear, the eardrum is stretched outwards, which reduces our hearing and causes pain. We yawn, which causes the Eustachian tube joining the throat to the inner air to open, and the air rushes out of the inner ear, causing a popping sound. When we are descending, the same thing happens in reverse. Aug 30 06, 7:06 AM