Farts are magical puffs of hilarious sounding gas produced by the human ass. They are the standard of all jokes, with funniness being measured in farts.
A fart is a combination of normal, everyday gases and small indigestible molecules from your food.
Nitrogen: 20-90% - Since nitrogen is the primary component of our atmosphere, it is also the primary component of your flatulance. It's basically useless filler: the talcum powder of your ass air.
Carbon Dioxide: 10-30% - CO2 presence in a fart is miniscule in comparison to nitrogen, but it is one of the more abundant chemicals in them. CO2 volume is increased if you drink a large amount of carbonated sodas or drinks. It is present primarily because your body produces it as waste during respiration and digestion.
Hydrogen 0-50% - How someone could have a 50% hydrogen fart is a foreign concept, however it is abundant in your farts from the foods and liquids that you ingest. If you had a half-hydrogen fart, you may very well explode yourself if you lit it.
Oxygen 0-10% - Ends up in your farts the same way that nitrogen does.
Methane 0-10% - People commonly think that methane makes farts stink. This is false, as methane is odorless. However, like hydrogen, methane is flammable so it does enable you to light a fart and injure yourself.
Sulfur compounds and thiols (mercaptans): trace amounts - These are what make your farts actually smell like chili or eggs or garbage. Or egg-chili garbage. These chemicals include hydrogen sulfide (rotten egg smell) and dimethyl sulfide (probably also some sort of rotten egg smell). Some of these chemicals are produced by bacteria within the intestines. However, sulfur rich foods like beans, onions, and eggs enable people to produce farts that are much more rancid than normal.
Feces: anywhere from trace to 100%- Yes, farts, if nasty enough, can contain fecal matter, which is composed of bacteria, water, and fiber/other indigestible materials. If you're close enough to having a bowel movement, or have just eaten an unhealthy amount of diarrhea-inducing food, you may shart. If you don't know what a shart is, go see Along Came Polly. It's a fart that's all feces, if you get my drift.
Farts, just like any other quasi-perverted word, have developed a huge number of synonyms over the years. These include, but are probably not limited to: flatulence, flatus, passing gas, breaking wind, poot, toot, ripping one, cutting the cheese, ass-whistle, ass blast, butt thunder, backdoor breeze, butt trumpeting, and my personal favorite, airbrushing your boxers. Feel free to post more in the comments, because this list could probably continue for 44,878 more lines of text.
This is normally attributed to excessive bacterial action. This makes sense as bacterial chemical reactions produce heat and sulfur-based chemicals. As for stank farts being quiet, that is similar but a little more complex. These bacterial reactions cause very small amounts of gas to be released...usually too small to cause an ass uproar. Typically, farts are very high in airborne gases. Since these farts have less air in them, they are generally more concentrated and vomit-inducing.
According to South Park, which according to all science is a reputable source, we fart so that we do so spontaneously combust. However, it is actually from peristalsis, which is basically doctor-nese for your intestines passing food through your body. This causes both air that you swallow and gases from the food being broken down being pushed through your body and ultimately out your butt.
Just like everything else ever farts have fetishists and obsessors. The infatuation is called flatulophilia. Flatulophiles are usually male, which explains the existance of fart fetish porn. Farts are indeed funny, and do deserve proper recognition as a legitamate form of jokery. However, this may be taking it a bit too far. Flatulophilia sounds like an embarrassing problem, and people would probably be very unlikely to admit to being a fart sniffer.
Many people have employed different techniques for covering up farts. Most people try to cough or shout over the fart. Some people, according to the internet, put toilet paper or something similar inside their underwear to muffle the sound. There even exist pads that are intended to actually be inserted into your underwear and do just that. Yeah, never search for something so stupid on the internet. The best method is to train your butt to have a built in silencer, but this takes practice. Try not to sit on vinyl surfaces while letting one rip, and they tend to exacerbate the sound. Also, covering up farts should only be done around people you don't know, and you should always take advantage of farts if the situation calls for it. After all, past experience says that most anyone will laugh. If they don't, promptly tell them they don't have a soul.