The process of fart mixing into ambient air generates heat.
No, it does not generate heat. It carries a portion of heat from the body and transports it into the ambient air in the room. Almost simultaneously, an equivalent amount of air leaves the room to the outside. The increased heat of the air yields into an increased temperature in the room.
Granted, it’s not intuitive without getting deep into the weeds of thermodynamics, but when different molecules that are attracted to one another get mixed, that combined form is a state with lower chemical potential energy than the original substances would have if left separate. I.e. you’d need to invest energy to break up the intermolecular attractions if you wanted to re-separate the molecules. The potential energy “lost” in the process of mixing is extruded in the form of heat.
I have a degree in physics and work in biomed R&D. I am a qualified fart scientist — this is what I live for.
The energy change can be regarded as being made up of three parts: the endothermic breaking of bonds within the solute and within the solvent, and the formation of attractions between the solute and the solvent.
Does not sound like mixing of gases. No bonds are broken. No bonds are formed. Just (almost) free molecules moving around.
As my profession is solid mechanics, mixing of fluids is not my field of expertise.
We are talking about mixing of gases, not the solution of a liquid in a gas or a solid in a liquid.
Here, no bonding forces are broken as there are almost none active. Air as a mixture of gases at low pressure is, at least like I have learned in thermodynamics, treated as if its different components don’t interact with each other. For each component, the state equation is evaluated individually using its partial pressure.
Of course. Otherwise this would qualify as a chemical reaction.
I’d totally get it, if were taking about lets say vaporising of perfume or fuel. There, the bonding forces between the molecules of the liquid (van der Waals, H-bridges) are released, and thus stored energy is set free.
I was focused on the marginal effect no matter how small, but you’re right that heat of solvation for gases is minuscule. I’m won over on the idea that it would be outweighed by cooling effect of gas expansion from fart decompression.
No no, dissolution does generate (sometimes negative) heat. It’s called heat of solvation and it exists because when something dissolves it breaks solute-solute bonds, requiring energy, but then forms solute-solvent bonds, releasing energy. This difference can either result in the solution becoming hotter or colder than its components.
Okay this is apparently one of those things where you’ll get different answers depending on who you ask (even different Wikipedia articles give different answers), but this is a matter of semantics. No matter what you call it, mixing on a molecular level will result in the release or absorption of (in the case of gases a very small amount of) heat.
The edge cases, so mixing very polar with very nonpolar gases has deviations in enthalpy. Very tiny, but they exist.
Mixing inert species like nitrogen, CH4 or oxygen (anything human, fart or air related) does not result in a change in enthalpy. All it does is increase entropy. They are essentially ideal gases under these conditions, nothing happens.
Which Wikipedia article? Please name them so they can be corrected.
Heat does not get absorbed. Semantics or not, these words have well defined meanings.
Not much, except the pressure involved is different. Breathing takes place at almost ambient pressure, fatting involves larger pressure release. Thus, while breathing is an almost isochronic process, for the air you exhale, no air will leave the room, but flatus expands when released to the environment.
Also flatus contains more methane, carbon oxides and fancy molecules than the air we exhale usually does, which contains more water than flatus.
Exactly, beside one techniallity:
No, it does not generate heat. It carries a portion of heat from the body and transports it into the ambient air in the room. Almost simultaneously, an equivalent amount of air leaves the room to the outside. The increased heat of the air yields into an increased temperature in the room.
The act of mixing fart into air is an exothermic process that does in fact explicitly generate heat. You can read up here if curious: https://en.wikipedia.org/wiki/Enthalpy_change_of_solution
Granted, it’s not intuitive without getting deep into the weeds of thermodynamics, but when different molecules that are attracted to one another get mixed, that combined form is a state with lower chemical potential energy than the original substances would have if left separate. I.e. you’d need to invest energy to break up the intermolecular attractions if you wanted to re-separate the molecules. The potential energy “lost” in the process of mixing is extruded in the form of heat.
I have a degree in physics and work in biomed R&D. I am a qualified fart scientist — this is what I live for.
But isn’t there some contribution from the delta in pressure?
Yeah, you’re right — there would be some cooling from pressure release.
I might need to do some math tonight.
Qualifies mixing of gases as dissolution?
Does not sound like mixing of gases. No bonds are broken. No bonds are formed. Just (almost) free molecules moving around.
As my profession is solid mechanics, mixing of fluids is not my field of expertise.
In a nutshell, the bonds in question are intermolecular forces, not bonds between atoms within a molecule.
Still not a solution.
Care to elaborate on your stance?
Each molecule is on its own. There is nothing to dissolve. No bonds to break.
We are talking about mixing of gases, not the solution of a liquid in a gas or a solid in a liquid.
Here, no bonding forces are broken as there are almost none active. Air as a mixture of gases at low pressure is, at least like I have learned in thermodynamics, treated as if its different components don’t interact with each other. For each component, the state equation is evaluated individually using its partial pressure.
Of course. Otherwise this would qualify as a chemical reaction.
I’d totally get it, if were taking about lets say vaporising of perfume or fuel. There, the bonding forces between the molecules of the liquid (van der Waals, H-bridges) are released, and thus stored energy is set free.
Yeah, that’s fair.
I was focused on the marginal effect no matter how small, but you’re right that heat of solvation for gases is minuscule. I’m won over on the idea that it would be outweighed by cooling effect of gas expansion from fart decompression.
Did you already find information on how much pressure a colon can sustain or maintain?
No no, dissolution does generate (sometimes negative) heat. It’s called heat of solvation and it exists because when something dissolves it breaks solute-solute bonds, requiring energy, but then forms solute-solvent bonds, releasing energy. This difference can either result in the solution becoming hotter or colder than its components.
This is not happening here. There is no solution, everything is a gas.
Yeah solutions can have any phase of solute and any phase of solvent. The most common example of a solution of gases is the air, so yeah.
No. Gas in gas can not be a solution. The solvent must be a solid or liquid.
Okay this is apparently one of those things where you’ll get different answers depending on who you ask (even different Wikipedia articles give different answers), but this is a matter of semantics. No matter what you call it, mixing on a molecular level will result in the release or absorption of (in the case of gases a very small amount of) heat.
The edge cases, so mixing very polar with very nonpolar gases has deviations in enthalpy. Very tiny, but they exist.
Mixing inert species like nitrogen, CH4 or oxygen (anything human, fart or air related) does not result in a change in enthalpy. All it does is increase entropy. They are essentially ideal gases under these conditions, nothing happens.
Which Wikipedia article? Please name them so they can be corrected.
Heat does not get absorbed. Semantics or not, these words have well defined meanings.
Is it any different from hot air exhaled from your lungs?
Not much, except the pressure involved is different. Breathing takes place at almost ambient pressure, fatting involves larger pressure release. Thus, while breathing is an almost isochronic process, for the air you exhale, no air will leave the room, but flatus expands when released to the environment.
Also flatus contains more methane, carbon oxides and fancy molecules than the air we exhale usually does, which contains more water than flatus.