SORU: aşağıdaki parçaya göre cevaplayınız
According to the passage, during an aircraft descent or an underwater dive, it is highly probable that —.
The ear (eels blocked when the air pressure in the space behind the eardrum, that is to say, the middle ear, is different from external air pressure. Normally this is not a problem because air is supplied to the middle ear from the outside through a narrow tube at the back of the nose, which is called "the Eustachian tube". This is usually closed, but yawning or swallowing opens it up sufficiently to permit the internal and external pressures to equalize. Tilting the head back also helps because of the way in which the Eustachian tube is positioned in the head. If the tube Is blocked, as when we have a cold, a difference in pressure gradually builds up. This stretches the eardrum and makes sounds seem muffled. Problems can also arise when there is a rapid change in external pressure during an aircraft descent or an underwater dive. This is one of the reasons why infants and children start crying while the aircraft is descending. The secret in all cases is to use your cheek and throat muscles to create a pressure that opens up the Eustachian tube.