When you encounter a loud noise, why should you open your mouth or shut up and block your ears with your hands?

A: When you hear a loud noise, the pressure on the eardrum suddenly increases due to the violent vibration of the air. At this time, opening the mouth can make the pressure inside and outside the eardrum equal (because the inside is connected) and avoid the eardrum from being damaged;

If you shut up and block your ears with your hands at the same time, the noise will weaken the noise at the receiving place and prevent damage to your ears.