How do people hear explosions and why are they so loud?

Question

How do people hear explosions and why are they so loud?

Answer 1

you hear sound because of a pressure wave that travels through the air; any pressure wave - when you listen to music, when you talk, when you drop a pin.

When something explodes, all of that energy (mostly thermal expansion) creates a HUGE pressure wave - so huge that all of those sound waves start to pile up (because they can't go faster than the speed of sound) to create a Shockwave (the same thing that causes the 'crack' of a rifle shot, or of a sonic boom, or the shock of a nearby lightning strike.

This is what you startles you and what makes your chest thump when you hear an explosion.