(Pre-reading reminder: Please do not read this article while eating)
Zi Yue: "The fart doesn't stink, the stinky fart doesn't sound." (Confucius: I didn't say that... ）
Studies have shown that a normal person will fart 10 to 15 times a day, excreting about 500 ml of gas. Among them, the sound fart is about 1-2, and the silent fart generally accounts for more than 10
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Look at this shocking data! As such a common daily compulsory course, think of the smell that rises silently in the elevator, think of the sound of a cold tearing cloth in the conference, office, classroom, library, and think of the brave swimmers in the swimming pool who bubble up at the end and can "breathe" at both ends.
What is this god asking??? (From Zhihu)
If it were not for the strong psychological quality of the elder brother who asked the question or such a strange bedroom competition project, presumably when experiencing the above situation, whether you are the maker of the fart who is at the scene of the social death, or the recipient of the "fart torture" who experiences the double torture of smell and hearing, the inner questioning will definitely rise like this light and fluttering gas: this
Is it the degeneration of morality, or the annihilation of human nature?!
Today, we will analyze and analyze the relationship between loud farts and stinky farts, and come to an academic spiritual feast of hearing and smell!
Parsing of farts
Although this subtitle sounds weird... But, parsing farts, we're professional.
What is a fart? It is a gas mixture consisting of 59% nitrogen, 21% hydrogen, 9% carbon dioxide, 7% methane, 3% oxygen and 1% other trace components. From this analysis, the smell of farts is all "attributed" to the other trace components of the 1%.
This 1% contains ammonia, hydrogen sulfide, fecal stink, volatile amines, volatile fatty acids and so on. Readers who know a little about chemistry tend to smile when they see these substances, because most of them are really "notorious" names.
Structural formula of faecate stinkin
Fleasterin, or 3-methylindole. It is "flattering": at low concentrations, it has a jasmine fragrance. It is the soul of the fragrance of certain flowers and can be used to make food spices, perfumes, etc. At this time, it is often renamed "Jasmine Essence"... (On the importance of a good name.)
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It is also "annoying": at high concentrations, it has a fecal odor, such as "taste as its name", is one of the sources of "fecal odor", is also one of the sources of odor such as snail powder, stinky tofu, etc., it also creates a certain degree of smell of cattle, sheep, and so on
The source of the fart
The gas in the fart is mainly derived from the gas we swallow when we eat and talk; on the other hand, it also comes from the metabolites of intestinal microorganisms in the process of life activities, just as animals exhale carbon dioxide during breathing, and plants release oxygen in photosynthesis; at the same time, the chemical reaction of chemicals in food in the intestine may also produce gas, such as hydrochloric acid in stomach acid and sodium bicarbonate in food to produce carbon dioxide.
When these gases mix, they gradually move downwards as the intestines move. It stimulates the receptors of the intestinal wall, and with the excitement of nerve conduction, you feel a throbbing. At this time, you have a reconnaissance of the surrounding situation, and fortunately, everything is appropriate. actuate! The sphincter at the anus was dilated, and after some twists and turns, the impatient gas finally slipped away!
But – if you're unlucky, you're in a meeting/subway/even giving a speech (don't think it's impossible!). In the 2008 US election, Hillary Clinton was on the scene of the live broadcast of the TV debate, because she overestimated her control ability, and let go of a loud fart! Apparently, the situation is not up, and it just so happens that you are luckier than Hillary to "hold back" back! The gas can only return to the same way, and becomes - hiccup ... (A small amount of gas is also absorbed through the intestinal wall into the bloodstream and metabolized by the liver.)
Fart? Stinky farts?
As the saying goes, "A fart doesn't stink, a stinky fart doesn't sound." At first glance, it is thought to be pseudoscience, but when you think about it, it has a good theoretical basis.
In order to explain this sentence, please: go up to the hall, get down to the kitchen; can send rockets to the sky, can make ships swim in the water, and have superpowers of fluid mechanics shine on the scene! It tells us the story behind this sentence.
It is easy to understand that water is a fluid. In fact, air is also a fluid because they all have fluidity (relative movements between parts of matter).
Fluids in real life are mostly sticky fluids, and farts are no exception. Under the influence of viscosity (internal friction when flowing), it has two ways of flowing:
At small speeds, there is generally a phenomenon of "calm and stable" layered flow, called laminar flow;
When the velocity increases to more than a certain value, there will be mixing between the various spheres, and sometimes a whirlpool will be formed, and there will be a "chaotic and unstable" turbulent flow.
Laminar flow (top two) and turbulence (bottom two) (source network)
Turbulence (source network)
In the practical application of medicine, turbulence is distinguished from laminar flow by the fact that it emits a sound when the fluid is turbulent (for example, the doctor can judge the blood flow status by listening to the sound of the heart with a stethoscope, and the air flow situation and infer the breathing state by listening to the sound of the lungs to make a diagnosis). Part of the source of "fart sound" is also here, that is, the sound produced by turbulence. In practice, in the face of the strong deception of the Kikube undercurrent, we really don't know whether the next fart is a stinky fart or a loud fart. So, I'd like to call it: Schrödinger's fart.
In theory, how to determine whether the state of a fluid is laminar or turbulent? The Reynolds number (Re, a dimensionless number used to characterize the ratio of the inertial force to the viscous force of a fluid) is required.
Definition of a Reynolds number
In the formula, Re is the Reynolds number, v is the flow rate of the fluid, ρ is the density of the fluid, r is the radius of the flow pipe, and η is the viscosity of the fluid
The Reynolds number was proposed by the British physicist Osborne Reynolds in 1883 after extensive analysis of experimental data. Here, we just need to remember that the larger the Reynolds number, the more likely the fluid is to be turbulent; the smaller the Reynolds number Re, the more likely the fluid is to be laminar. (In fact, when Re < 1000, the fluid does laminar flow; when 1000 < Re<1500, the fluid flow state is unstable, and it is in a transition state between laminar flow and turbulence (transitional flow), which can be transformed into each other; Re>1500, the fluid does turbulent flow)
ANALYZE TIME.
With the weapon of Renault number, you can finally do a big job! For a fart with the same velocity (v), "chrysanthemum" diameter (r), and density (ρ), the Reynolds number depends only on the viscosity of the fart (η). The viscosity of the fart depends on the mucus in the intestine; hydrogen sulfide gas is also derived from the mucus in the intestine. That is, the more hydrogen sulfide gas (the more smelly the fart), the greater the viscosity (η) of the fart.
According to the definition of the Reynolds number, the greater the viscosity (η) of the fluid, the smaller the Re will be, so that the fluid tends to laminar flow.
At this point, combined with the above analysis and the characteristics of laminar flow silent and turbulent sound, the problem is solved: in general, the viscosity of stinky farts is large, it is easy to occur calm and stable laminar flow, and it is not easy to make sounds, so - "stinky farts do not sound"!
Play with Reynolds numbers!
"Farts don't stink, stinky farts don't stink" was explained. In order to avoid social death, how to mute the fart?
If we look closely at this definition, it is not difficult to find that in the face of a fart, remove the gas density (ρ) that we are difficult to influence and change, but fortunately, there are still the following effective ways to release a silent fart:
1. Reduce the flow rate of the fart (v)
We reduce the anus to a perfectly circular hole with a radius of r. Then, by the fluid flow rate (Q) calculation formula: Q = S·v, and then substituted into the area of the anus, facing a certain flow of fart, according to the following derivation: expanding the diameter of the Kikube area can be extremely effective in reducing the flow rate of the fart, thereby reducing the Reynolds number Re. Moreover, according to our deduction, there is no need to worry about the resulting increase in the Reynolds number.
2. Increase the viscosity of the fart (η)
From the definition formula of the Reynolds number, it can be seen that when the viscosity of the fart (η) increases, the Reynolds number will decrease.
That being said, according to the previous analysis, this is at the expense of fart freshness or at the expense of friends (bushi)! (Experiments are risky, try with caution)
How to increase the hydrogen sulfide component in the fart? Quite simply, the more protein is consumed in general, the more hydrogen sulfide is produced by the intestinal flora that metabolizes proteins.
3. Skillfully control the muscles in the Kikube area
Sound comes from vibration, and fart sound comes from the vibration of muscles at the same time as the turbulence of gas. For example, when the lips are tight and exhaled, the lips will not have any vibration; when the lips relax and exhale, there is a certain probability that the lips will vibrate happily with the flow of air, making a "poof" sound.
Vibrating sound of tuning forks (source network)
While I understand that the experience was not very good (I sincerely apologize for this), it must be admitted that there is still a great degree of similarity between the two... Given that chrysanthemums are also like this, when spanking, it is recommended to properly tighten the muscles and use their own strength to provide a stable flow tube to compete with farts!
This skill is difficult and requires everyone to practice diligently. I look forward to receiving the good news that everyone has practiced the silent killing skill of controlling Kikube muscles at will as soon as possible!
summary
In this article, we use fluid mechanics to teach you how to turn on the mute mode of farts by analyzing the past and present lives of farts.
I didn't expect that there was such a mystery hidden inside the little fart. You might not have thought that in order to avoid social death and learn to release a silent fart, we actually studied fluid mechanics and entered the world of "keeping to ourselves" laminar flow and "lively and extraordinary" turbulence.
So, you have to know: the sound of tearing the rag when farting is essentially the same as the sound of blood breaking through the barrier when measuring blood pressure; the "silent laminar fart" we want to create is similar to the design idea of laminar flow operating room; further study of laminar flow and turbulence, we can diagnose the heart through the sound obtained during auscultation... Among all things in the world, the same set of physical laws is the common "mastermind behind the scenes", and the connection between them is so inextricable that it can be described as "the unity of the world".
At a certain time in the future, in a certain year, month, and day, when trillions of gases in your intestines gradually accumulate, they will collide with each other, break through the obstacles of muscles, drill small holes, and make a loud sound of breaking through the air.
If so, hopefully you'll remember this tweet in this instant. Congratulations to yourself, for you are asking a question that even God cannot understand.
I'm going to ask God two questions, one is quantum mechanics and the other is turbulence. I reckon the first question has an answer.
—Werner Carl Heisenberg
bibliography:
Duan Yunfeng. Xiao Belly Knows the Intestine: Careful Thinking of Intestinal Bacteria. Tsinghua University Press.
Xiong Xingliang, Chen Longcong, et al. Medical Physics. Science Press.
[3] J.P.Eckmann. Roads to Turbulence in Dissipat-ive Dynamical Systems [J]. Review of Modern Physics,Vol. 53, No.4, pp. 643～654, 1981.
Wang Lei, Ji Min, et al. Medical Physics 9th ed. People's Medical Publishing House.
(Cover image source network)
Source: Hydrocarbon Warlock
Edited by: Half Seven, yr Lewis