Can You Really Outrun an Explosion?

An explosion occurs when a large amount of energy is released into a small volume of area in a very short time. The energy released comes in many forms, including chemical (artificial explosives), nuclear and hydrothermal (volcano eruptions).

Burning very rapidly, explosive material releases concentrated gas that expands quickly to fill the surrounding air space and apply pressure to everything in it. That is, it explodes in a blast powerful enough to blow away nearby trees, cars, buildings and anything else in its path [sources: Muller, Harris].

On the set of an action flick, blasts are often cultivated using nifty camera angles, CGI and miniature explosive devices, with notable exceptions like 2009 Oscar winner "The Hurt Locker" which used actual full-sized explosives. In real life, movie-type blasts require an explosive like C-4, TNT or gasoline, which cause explosions when they burn and mix with oxygen. C-4, for example, combines combustible material with plastic, often in a block form. The explosive is ignited using a detonator, which burns and causes the block to release a number of gases, including nitrogen and carbon oxides at a very fast rate and with a whole lot of force (the explosion) [sources: Harris, Failes].

And those fiery automobile explosions that are the centerpiece of any good car chase scene? More likely caused by strategically placed C-4 than an explosion in the gas tank. These days, cars on the street are equipped with highly durable gas tanks precisely to prevent them from detonating in the event of a crash. It is also important to remember that gas burns in vapor, but not liquid form. That means that, even if a car's tank were ruptured, the liquid gas in it would have to convert to vapor, mix with the air in the proper proportion, and be ignited in order to the car to blow up.

When an explosion of big screen proportions does happen, however, it engulfs the surrounding area in a heartbeat. Think you can outrun it? Read on, and then think again.

The simple answer is: No, you cannot outrun an explosion. But it may depend on how close you are to the explosion when you start running. And how fast you are.

A C-4 explosion, for example, is virtually instant. Gases are released from the explosive at the super speedy rate of 26,400 feet per second (8,050 meters per second), pummeling everything in its immediate wake. In other words, if you are within 26,400 feet or so of an explosive, you will get hit by the blast within one second, assuming it is powerful enough to reach you [source: Harris].

By comparison, Jamaican sprinter Usain Bolt set a world record at the Beijing Olympics by running 200 meters (656 feet) in 19.30 seconds. That's about 10.4 meters or 34 feet per second. On the set of a real-life action flick, Bolt's lightning fast pace would not have prevented him from going up in flames, so to speak [source: Olympic.org].

That's assuming that Bolt or any other explosion racer is standing in the vicinity of the blast. Of course it is possible "outrun" an explosion if you are already pretty darn close to a safe distance away.

According to the U.S. Department of Homeland Security, the minimal safe distance from a 5-pound (2.2 kilogram) pipe bomb is 1,200 feet (360 meters). "Minimum evacuation distance is the range at which a life-threatening injury from blast or fragmentation hazards is unlikely," the department explains, adding that a person within the safe zone may still suffer injuries that are not life-threatening. The evacuation distance rises with the size of the explosion, from a 50-pound (22-kilogram) briefcase bomb (1,850 feet or 564 meters) to a 1,000-pound (453-kilogram) explosive device in a van (2,400 feet, 732 meters) and a 60,000-pound (27,180-kilogram) tractor trailer bomb (9,300 feet, 2,835 meters).

In other words, should you find yourself rappelling an exploding skyscraper from a dangling fire hose, you're likely to come out with more than just a crispy, interestingly-colored undershirt.

Still thirsting for some high-powered action? Check out the links that follow for more information on C-4, bomb sniffing and even internal human "explosions."