When the plane takes off or descends, its ears are particularly uncomfortable, and there is a feeling of rising in the middle. What is the reason? Thank you.

This phenomenon is actually related to atmospheric pressure. According to the measurement, the atmospheric pressure per square centimeter at sea level is equal to the weight of 760mmhg (1 mmhg =133.322pa). However, with the increase of altitude, the atmospheric pressure will gradually decrease. At an altitude of 9 kilometers, the atmospheric pressure is only equivalent to 230.4 mm Hg. Our ears are composed of three parts: the outer ear, the middle ear and the inner ear. The outer ear and the inner ear bear the same pressure as the atmospheric pressure, while the middle ear adjusts the pressure by opening and closing the small tube leading to the nasopharyngeal cavity-the eustachian tube. When the external air pressure changes sharply, the eustachian tube cannot be opened in time, which will lead to ear swelling and hearing loss.

Generally speaking, air is more likely to leak from the middle ear to the nasopharyngeal cavity, but it is more difficult to enter the middle ear from the nasopharyngeal cavity. Therefore, when the plane takes off, the pressure in the middle ear is greater than the outside world, and air easily leaks into the nasopharyngeal cavity, so there is less discomfort. However, when the plane descends, the pressure of the outer ear and the inner ear rises with the atmospheric pressure, the middle ear presents negative pressure, and the eardrum invaginates, so we will feel that the ear is swollen and uncomfortable, as if it is separated by a membrane. In order to eliminate this phenomenon, we can open the eustachian tube by swallowing, chewing and yawning to balance the pressure inside and outside the middle ear.