Reality Check is an irregularly appearing column dedicated to giving you what you need to make games more realistic. We'll try to dispel myths and give you the lowdown on everything from armor piercing rounds to castle construction. If there's a topic you'd like us to cover, drop us a line. This month, we turn our attention to an action film staple - explosions.

Things That Go Boom

Explosions have been the meat and potatoes of action/science fiction films ever since Star Wars kicked off about a million of them in 1977. The cinema of spectacle has slowly shifted over the past thirty years from "women's films" - emphasizing costumes, dance routines, and so on - to "men's films" - emphasizing steroid-laden übermenschen with large weapons who blow things up real good.

The raw vision of watching a huge fireball blossom on screen can be breathtaking if done properly, and role-players have often utilized such mayhem in their campaigns. I mean, who doesn't love the visceral thrill of detonating thirty pounds of explosives beneath a Chevy Impala, or shortening a skyscraper by, oh, say twenty stories?

Blowing Up Some Myths

While movie explosions can be loads of fun, they can also be some of the most blatant transgressors against the laws of physics on-screen. Sure, they look cool, but they'd give Isaac Newton fits, and the sad fact of the matter is, they just couldn't happen in the real world. Below is a list of motion picture truisms, some specific examples of where they occur, and why exactly they won't work.

1. Cars explode when you shoot them.

This has enough truth in it to avoid being totally ludicrous, but still perpetuates a lot of goofy misperceptions. The assumption is that a spark from the bullet ignites the gasoline tanks, which ruptures and sends the entire vehicle up in a dazzling display of special effects.

Fire requires a source to ignite it and oxygen to continue feeding it, neither of which are readily available in a standard gas tank. If a break occurs, and the gas leaks out, then an explosion, or at least a fire, is possible. But it still requires a source of ignition over and above what caused the break in the tank. And aside from tracers and incindiaries, bullets simply don't light things up like that.

2. Explosions lift people into the air and gently deposit them some distance away.

This has been used by more movies than I can count, but my favorite example is Master Thespian Cindy Crawford being flung from her balcony in the movie Fair Game. The top floor of her house goes up, sending glass, plaster and TV parts hither and yon, but she manages to land safe and sound in a nearby body of water.

The basis of this cliché is the idea of the shockwave which precedes the explosion. Cindy (or whoever) gets hit by the shockwave, which pushes her forward ahead of the explosion and the shards of mangling shrapnel it entails.

The difficulty here is that a shockwave of sufficient force to lift a human being off the ground is also powerful enough to cause horrific damage in the process. It would be the equivalent of hitting the ground at the speed the shockwave is moving, which would probably be enough to break every bone in her body.

If we assume that the shockwave isn't enough to squash her like a pancake, then there's still all the shrapnel from her totaled house to contend with. Considering that the entire top floor went bang, there would be enough flying bits of death around her to crimp that Maybelline complexion forever.

3. Ships will explode in outer space.

Words can't describe how much we love Star Wars, and maybe physics works differently in that galaxy far, far away, but space just doesn't allow for all those cool Star Destroyer explosions.

As stated earlier, fire needs fuel to consume and oxygen to combine with. Presumably, ships have air supplies which can supply enough for a decent explosion, but the amount of oxygen required to maintain it dwarfs in comparison to the vastness of space. Any rupture in the hull would cause an immediate vacuum, dispersing the air, putting out the fire, and leaving most of the ship intact.

And we won't even get into the sounds.

4. People can outrun explosions.

This originated with Raiders of the Lost Ark, when Harrison Ford outran the rolling boulder. Somebody thought that fireballs would be cooler than rocks, and since then, we've been treated to countless action heroes sprinting their way to safety while the expanding wall of flaming hurt closes in behind them.

Sorry. With nothing to hold it back, an expanding fireball will easily outdistance the world's fastest sprinter. The only realistic hope someone has is if they're already out of range of the explosion, meaning that they wouldn't need to run to save their hide.

Reality Check: Explosions Rebuttal