Yes... under normal conditions, the ET remains closed but it
opens up in chewing, swallowing, sneezing, yawning...
While ascending or descending an aircraft or in diving, you will
notice that it affects your hearing and may cause ringing of the
sound, because the tube is shut off as the pressure in the middle
ear is lower than outside.
To open it again and to maintain patency of the ET and to relieve
off the symptoms, consider pressing your nose and start blowing
till your ears go pop and this signifies the reopening of the
tube... this manever is known as the Valsalva maneuver...
