Farts are caused by trapped air, which can come from many sources.  Some of it is air that we have swallowed while chewing or drinking.  Some air is caused by gas seeping into our intestines from our blood, and some gas is produced by chemical reactions in our intestines or bacteria living in our guts.

A typical fart is composed of about 59 percent nitrogen, 21 percent hydrogen, 9 percent carbon dioxide, 7 percent methane and 4 percent oxygen.  Only about one percent of a fart contains hydrogen sulfide gas and mercaptans, which contain sulfur, and the sulfur is what makes farts stink.

Farts make a sound when they escape due to the vibrations of the rectum.  The loudness may vary depending on how much pressure is behind the gas, as well as the tightness of the sphincter muscles.

The more sulfur-rich your diet is, the more terrible your farts will smell. Some foods contain more sulfur than others, which is why eating things like beans, cabbage, cheese, soda, and eggs can cause gas that will peel the paint off the walls!

The average person produces about half a liter of farts every single day, and even though many women won't admit it, women do fart just as often as men.  In fact, a study has proven that when men and women eat the exact same food, woman tend to have even more concentrated gas than men.

If a person were to fart continuously for 6 years and 9 months, they would produce gas with the equivalent energy of an atomic bomb.

Though farts come out with varying velocities, we don't typically smell them for about 10-15 seconds after letting them rip.  This is because it takes that long for the odor to reach your nostrils.

Doctors disagree on whether or not holding in a fart is bad for your health.  Some experts think that farts are a natural part of your digestive system, so holding them in won't harm you.  Others think that at best, holding them in can cause gas, bloating, and other uncomfortable symptoms, and at worst, repressing gas can cause hemorrhoids or a distended bowel.

While most cultures feel that farts should be suppressed in polite company, there are some cultures that not only don't mind letting them fly in public, but they actually enjoy it.  An Indian tribe in South America called the Yanomami fart as a greeting, and in China you can actually get a job as a professional fart-smeller!

In ancient Rome, Emperor Claudius, fearing that holding farts in was bad for the health, passed a law stating that it was acceptable to break wind at banquets.

As stated above, the methane and hydrogen in bacteria-produced farts make your gas highly flammable.  This is why some people think it's a fun party trick to hold a lighter up to their bums and let one fly; doing so produces a big burst of flame, but is obviously very dangerous.

In rare cases, a build-up of flammable gasses in the intestines have caused explosions during intestinal surgeries!

It's hard to believe that the tiny termite is responsible for a great deal of our global warming problem on the planet.  Termites fart more than any other animal, which produces methane gas.  According to the Environmental Protection Agency, "Global emissions of methane due to termites are estimated to be between 2 and 22 Tg per year, making them the second largest natural source of methane emissions. Methane is produced in termites as part of their normal digestive process, and the amount generated varies among different species."

Even if you clenched your butt and held them in all day, the gas will escape once you relax.  What's more relaxing than sleep?

Here's proof that you can't escape passing wind, even after you're dead!  Up to three hours after the body dies, gasses continue to escape from both ends of the digestive tract, resulting in burping or farting noises.  This phenomenon is due to muscles contracting and expanding before rigor mortis sets in.