Board Thread:Questions and Answers/@comment-4928331-20120918112046/@comment-4928331-20130206003424

An explosion (or detonation, if speeds involved are faster than sound) is a violent release of energy that compresses air around it. The compression quickly propagates through air molecules in a shockwave. The shockwave, a mechanical force that's basically a large differential in air pressure, packs quite a punch and is what sends everything in its proximity flying.

The pressure wave can rupture eardrums quite easily. If it is strong enough, it can turn your internal organs into jello (through a process called cavitation) and kill you.

You can actually see shockwaves with a slow motion camera: http://www.youtube.com/watch?v=fGi0w7ycRKk

Note that not all Hollywood physics is accurate though. For example, a bullet hitting someone will not send him hurtling backwards. Not unless the guy who shot it is sent careening backwards as well - Newton's third law of motion: for every action, there is an equal and opposite reaction.