What will happen to your ears if you hear a loud noise?

When a loud noise hits your ears, the small bones in your ears briefly disconnect, in order to partially mute the sound. This helps to maintain hearing. However, in louder sounds, this manuever is ineffective. Normal conversation is about 85Db (Decibels). A lawnmower is about 90Db and, over 8 hours, can cause some (usually reversible) hearing damage. Gunshots are around 140Db, and can cause instant pain as well as damage. Higher overpressure gradiants (bigger noises) can of course do even more. Really loud noises, like a gunshot at close range, can cause deafness, ringing in your ears (tinnitis), and may actually damage the ear drum. All of these effects may be temporary, or they may be permanent.