Dear Dr. Rex: Well, I’ve been a fart fan for decades now, even got my girlfriend a little interested. My question is, why are some farts just big wind-bag blow-outs and some are more musical than an entire orchestra, and more pleasing to the ear, if not the nose?-Steve

Dear Steve: Decades, huh???? Cool……Steve, farts are like snowflakes. You can classify them, but in reality, no two are exactly alike (although the “holy shit I really should have had dinner before my hot date with the best looking girl I ever met” fart is pretty similar to the “holy shit I really should have had breakfast before my huge interview for the best job I’ll ever have a chance to get” fart).

There are many reasons for the varieties in pitch, volume, duration, texture, odor, mass, specific weight, combustibility, and raunchiness. I will explain. Of the many qualities listed above, we can really break any fart down into 2 major components. These are sound and smell. The general relationship between these 2 components can be expressed in the following basic equation:

XD/V=S
What this shows us is that as the volume of a fart goes up, the smell will usually decrease. The factors impacting that relationship are the duration of the fart and the other X variables. This basic relationship is really quite simple. The noise a fart makes (what we are referring to as volume) occurs as a result of the butt-cheeks slapping violently together. They are slapping together because the air being emitted is being emitted with great force. The faster and harder they slap, the louder the fart. This is perhaps easier to understand if we look at the inverse scenario: the dreaded SBD!!!!

In this equation, we use D=Duration, V=Volume and S=Smell, X=a Variable which is a function of what you have eaten within the past 48 hours, how much sleep you have had, various stress factors, and whether something has actually crawled up your ass recently and died (if something has crawled up your ass and died, we use the formula AXD/V=S where A=the thing that has crawled up your ass and how long ago it died).

The SBD (everybody knows this stands for Silent But Deadly) and its not-too-distant cousin, the SBV (Silent But Violent), are the smelliest farts known to man. The reason for this is that the gasses in an SPD/SPV are not expelled with great force at all, rather, they are leaked out like a small hole in a bicycle tire. Therefore, there is no butt-cheek slapping and no volume. Because of this lack of pressure, the aperture (asshole, asshole) remains open for a longer period of time, allowing the meandering methane (the slowest, stinkiest of all the inert fart gasses) to escape into the earth’s atmosphere.

In sum, when more pressure is exerted, there is more volume achieved. There is also less time for slow stinky gasses to crawl out of the butt and into your nostrils. I hope this was not too technical, but after all, I am the fart doctor.