1.        What is a fart?[1] Flatulence (farting) is caused by gas in the bowel (intestines). It may be caused by digestion, high-fibre foods or the by-products of intestinal bacteria. Also,air in small quantities (oxygen and nitrogen) may be swallowed along with food and liquid and also in people who are anxious. These are absorbed into the bloodstream from the small intestine. But some excess continue its journey through the bowel where it comes out in a fart.
2.        Why do some people fart often? Some people fart only a handful of times a day. Others can fart up to 40 times. The average is believed to be about 15 times.[2] With some 7 billion people in the world, each producing about 15 farts a day – there’s an average of 105 billion farts a day.
3.        How much fart is released in a day?  The average person expels 1/2 litre to 3 litres of gas a day. Bacteria in our guts convert the gas to a smaller volume which is then expelled through our anus. It is estimated that without bacteria in our gut doing this job, we would be expelling around 5 times the amount each day.
4.        What sort of gas is in a fart? The farted air consists of a cocktail of gases. These include methanenitrogen and carbon dioxide. These gases are by-products of the breakdown of food residue by good bacteria (probiotics) naturally residing in the colon. Careful analysis of intestinal gas has shown that it is comprised primarily of exogenous air and only a small amount of endogenous air.
5.        What smell is your fart? The smell of a fart varies. It depends on the ratio of gases. That is influenced by the foods we eat. Really smelly farts are from gas produced bybacterial fermentation.[3]  Expect your farts to smell a lot if you eat garlic, onions, spicy foods and drink beer.
6.        Why do farts make noise? Fart sounds are produced by vibrations of the anal opening.  Sounds depend on the velocity of gas expulsion and the tightness of the arse (sphincter muscles of the anus). Is a fart just a noisy blast with a random distribution of frequencies? Studies have shown the fart has a tonal quality. To get an idea of how it works down there, try producing its tone by placing the tongue between the lips and blow.
7.        What makes a fart stink? The odour of farts comes from small amounts ofhydrogen sulfide gas and skatole in the mixture. These compounds contain sulfur. The moresulfur-rich your diet, the more sulfides and skatole will be produced by the bacteria in your guts, and the more your farts will stink.
8.        When is farting illegal? The Roman Empire once had a law against farting in public places. It is not clear whether Roman farters get arrested or fined. And who will arrest a farting police-man? Or a farting magistrate? One thing is sure: this law would have caused a lot of fanning and finger-pointing. After all, it is a street-wise farter’s natural instinct to pretend to fan off the offending smell and point to others nearby as the culprit. This law was abolished during the reign of Claudius. It seems he was one of the greatest of farting emperors. Even today, people ask, what is worse – having an emperor with no clothes or an emperor of all farts?
9.        How does a fart travel to the anus?  The intestine squeezes its contents toward the anus in a series of contractions called peristalsis. This process is stimulated by eating. It is why we often need to fart right after a meal.  Peristalsis creates a zone of high pressure which forces all intestinal contents (gas included), to move toward the anusa region of lower pressure. Gas is more mobile than other components. Small bubbles coalesce to from larger bubbles en route to the exit.   
10.   To fart or not to fart?  It is better to fart it out than to hold it in. We all instinctively know that.  Without farts, toxic substances build up in your body and you can get sick from it.  Holding your fart (flatus retention) is a major factor in diverticular disease.[4]  It causes discomfort and even pain, bloating, dyspepsia (indigestion), pyrosis(heartburn). A gassy gut can be fatal. It once happened to a patient having a colon polypcauterized. Gas in the colon led to an electric spark which caused the patient’s bowels to detonate. The explosion blasted out the colonoscope and ripped a six-inch hole in the patient’s large intestine.