2989: Physics Lab Thermostat

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Physics Lab Thermostat

Title text: Hopefully the HVAC people set it to only affect the AIR in the room.

Explanation

This explanation may be incomplete or incorrect: Created by a BOLTZMANN BRAIN - Given the calculations mentioned in the comment, it would seem that the thermostat works normally in the way that turning it clockwise will increase the temperature. This should be mentioned and some kind of calculation like the one mentioned in comments section could be added for clarity/reference. Do NOT delete this tag too soon. If you can address this issue, please edit the page! Thanks.

A thermostat is often used to regulate the operation of heating and/or cooling for a room. This may take the form of a simple dial, graduated by desired temperature values typically marked Celsius or Fahrenheit, depending upon location. (But see 2292: Thermometer) Typically a person is expected to know what sort of temperature they will find comfortable, to have heating/cooling effects kick in as the wall-device detects a temperature more than a certain amount below/above that ideal. The basic design of a physical wall-mounted dial might relate the relative position of the dial against the current state of a bimetallic coil, switching on or off the relevant systems once conditions locally drift away from the chosen ideal.

In this comic, the thermostat is installed in a physics lab, with those that work there clearly being expected to be familiar with the Boltzmann constant, a more fundamental method of measuring temperature which relates the average kinetic energy of a particle in a gas with the temperature of that gas. The Boltzmann constant is defined as 1.380649 × 10^-23 J/K (joules per kelvin), a value that's used in the definition of SI base units.

Thus Randall imagines a physics lab having a dial that can alter the constant between 1.418 x 10^-23 J/K and 1.351 x 10^-23 J/K. If the average kinetic energy of gas particles remains constant when moving the dial, then changing the Boltzmann constant would change how this average energy is measured in kelvin (and therefore any other measure of temperature), thus "changing the temperature". The equation is E=kT where k is the Boltzmann constant. Notice that if E is the same, lowering k implies a raised T, so the thermostat 'works' as intended. The effective range of the thermostat, presuming it is set to "room temperature" of 23°C (73°F), runs from 15°C to 29°C (59°F to 85°F).

You can build this "thermostat" in real life and use it to "control the temperature" of the room, even if you just craft it out of two pieces of cardboard. Assume you want a nice and warm room temperature of 300 K (about 27°C or 80°F). Rather than controlling the nature of the airflow into the lab (or convection heaters/coolers around it), or indeed having any effect on anything, it sets the definition of "1 kelvin" to a value between "each degree of freedom of every molecule has on average 1.418 x 10^-23 J" and "each degree of freedom of every molecule has on average 1.351 x 10^-23 J" that would correspond to the current warmth in the room being 300 K. With less energy needed for each kelvin, you have more of them.

There have previously been control panels for properties of the universe in 1620: Christmas Settings and 1763: Catcalling.

Because the Boltzmann constant is primarily concerned with the nature of temperature within a gas, the title text expresses concern that it might not only be applied to the air (hence the capital letters) in the room. Aside from the possibility that those responsible for the heating, ventilation, and air conditioning (HVAC) of the room could perhaps directly enhance or suppress the temperature in all the solids and liquids within the room, in unknown and not necessarily desirable ways, there may also be a secondary joke in which high voltage forms of alternating current (also referred to as HVAC) are influenced, in the related but distinct use of the measure for 'thermal voltage'.

Transcript

This transcript is incomplete. Please help editing it! Thanks.

[A black circular dial is shown with a white indicator line at the upper right. The label above the dial, enclosed in a rectangular box, says:]

Local Boltzmann Constant

[The two extremes of the dial are labeled as follows, the first value on the left and the second value on the right:]

1.418×10^-23 J/K

1.351×10^-23 J/K

[The indicator line is pointing to a position on the dial somewhere around 1.375×10^-23 J/K (between the 12th and 13th large ticks clockwise out of 19 total).]

[Caption below the panel:]

Physics Lab Thermostat

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Discussion

Assuming I did the math right (Units proved the units worked out, but I wouldn't otherwise assume that), holding the energy constant at "room temperature with the normal, global Boltzmann constant" this thermostat varies from 13°C (56°F) on the left to 28°C (82°F) on the right. Holding the temperature constant gives a much harder to interpret range of energies from 4.2 zeptojoules on the left to 4.0 zJ on the right. Turning those back into temperatures with the normal Boltzmann constant gives 29°C (84°F) to 15°C (59°F). Given the reversed scale, I'd assume the former is the intended interpretation, and this thermostat has no effect on local thermal energy, it just adjusts the temperature scale so the number on your (local physical constant variance-compliant) measuring device matches what you asked for. 162.158.62.243 05:28, 24 September 2024 (UTC) Will

No matter the scale, I'm sure glad that this one doesn't go up to 11. Zaktduck (talk) 07:56, 24 September 2024 (UTC)

Looking at the page history, I'm wondering if the "edit conflict" didn't kick in for some people. If this edit was performed over at least half an hour (quite possible), it would seem that useful edits (submitted after the start of that big addition) got wiped out. Seems unlikely that warnings happened but were deliberately over-ridden. I know this can sort of happen very soon after article creation (usually doubling-up 'first' edits), but it should have highlit any inadvertant re-editing of an interim-changed paragraph. I generally thought. 172.70.85.18 09:39, 24 September 2024 (UTC) ((Ironically, I got hit by an edit-conflict just now, someone having removed linefeeds above where I'm merely appending this!))

I don't understand it the same way as you guys. Through setting the Boltzmann constant to k=1.380649×10−23 Joules per Kelvin, it's actually the Kelvin that the SI is setting. Thus, changing k in an unchanged universe changes the definition of the Kelvin, and (presumably) of Celsius or Fahrenheit too, meaning that the "temperature" reading of the room is changed without any need for heating or aircon, it's just the number which is adjusted to whatever people ask. --172.71.164.106 10:25, 24 September 2024 (UTC)

I like this explanation. We have a thermostat like that where I work. The numbers change, but the actual temperature does not. --162.158.158.188 11:27, 24 September 2024 (UTC)

As I read it, yes it just changes the thing that relates heat to temperature (thus not changing the sum quantity of heat), but I am not convinced that the derivative idea of Temperature doesn't have some latent qualitative effect upon the experience. The additional amount of heat in a cinder might ignite some flammable substance, the same additional heat in a brick would be barely above its normal temperature, for example. Thus conceivably the temperature from the concentrated heat-source has more bearing upon what results than the less dense 'additional heat' with lower temperature that may never invoke the vapour-threshold/flashpoint.

Without being able to divorce or disassociate the interdependency (together with density/heat-capacith/etc), I can't be sure that such weirdness won't happen, and would not be surprised if things did (e.g. key phase-changes shift around). Like making inertial and gravitational mass independantly evaluated from each kter (if possible) would have certain real-world implications. (As well as hint that there's far more fundamental 'physics' at work than it is assumed that either/both currently are, in either newtonian or einsteinian respects.)

I think the explanation can cover both "just recorded different" and "changes physics" in a broad scope (which is somewhat hinted at right now). But it might be in the eye of the reader (and editor) how well it does that. 172.70.86.38 12:26, 24 September 2024 (UTC)

I note that "AIR" is in all caps. Is it supposed to be an Acronym? 12:28, 24 September 2024 (UTC)

No, that's just for emphasis: it's only the AIR that changes. 172.71.194.171 12:33, 24 September 2024 (UTC)

You are both right. AIR means AIR In Room. Caution: This comment contains recursive text: First you curse, then you curse again. 172.71.167.213 14:07, 24 September 2024 (UTC)

Huh... Everyone's saying "Energy is constant, Temperature number is changing.". But in that case, why would he be worried about it affecting things other than air? What if the Temperature was constant, and the Energy was what was changing? Then the dial would be doing something, and his concern over it affecting solids and liquids would be more warranted. 172.70.178.137 15:04, 24 September 2024 (UTC)

The current explanation is terrible: (1) It doesn't explain well, spending way too much time on introductory and trivial pedantry than getting to the point of the joke and the concepts necessary to understand it. (2) It's way too long. And (3) the prose is terrible. My high schoolers wouldn't be allowed to use / as a synonym for "or", but that's just the beginning of the poor style, confusing grammar, and the kind of English which screams neurodiversity and home schooling.

There is no doubt in my mind that ChatGPT can do better. 172.69.33.63 16:14, 24 September 2024 (UTC)

Proof:

This comic is playing with the idea of a "physics lab thermostat," but instead of controlling temperature, it humorously suggests adjusting the Boltzmann constant (a constant that links temperature and energy in physics, writen as 1.38×10⁻²³ J/K, where J is joules, a unit of energy, and K is kelvins, a unit of temperature). The dial shows different values for the constant, implying that it can be changed, which is absurd because the Boltzmann constant is a fundamental number that stays the same throughout the universe. In reality, you can't change the Boltzmann constant, so the comic is making fun of the idea of a scientist casually adjusting a fixed law of physics as if it were something simple like room temperature.

If the Boltzmann constant could be changed, it would directly affect how we experience temperature. The constant determines how much energy particles have at a certain temperature. If the constant were increased, more energy would be associated with the same temperature, so everything would feel hotter even if the temperature stayed the same. On the other hand, if the constant were decreased, less energy would be associated with the same temperature, and everything would feel colder than usual.

Beyond just how we feel, altering the Boltzmann constant would disrupt all sorts of processes that depend on temperature, like how fast chemical reactions happen or how heat moves around. A higher constant would make particles move faster and carry more energy at a given temperature, while a lower constant would slow things down.

The title text builds on the absurdity of being able to adjust the Boltzmann constant. It suggests that if the constant could be changed, hopefully, it would only affect the air in the room and not the entire universe. Imagining that the HVAC (Heating, Ventilation, and Air Conditioning) system could contain such a change to just the room's air shows the ridiculousness of trying to isolate the effects of altering a universal constant.

How is that not better in every way than the current human version? 172.70.206.157 16:33, 24 September 2024 (UTC)

It has the usual "Using wikipedia to write a book report on something you haven't read" issue that LLMs have. It retreads the same ground multiple times, explains both the humor and science only in the most surface manner, and gets the effects backwards in the section about particle energy. It also fails to explain the alternate, also humorous, interpretation of keeping pV/T constant while changing only the units we use to measure temperature with no actual effect. Scorpion451 (talk) 17:16, 24 September 2024 (UTC)

It's far more concise than what's up at present. How does it get the effects backwards? It describes the same effects of turning up the dial as the existing explanation. I don't understand the alternate explanation, which I don't think can be an explanation since the comic doesn't refer to pV/T. 172.71.142.47 18:11, 24 September 2024 (UTC)

There is nothing in the article page history mentioning pV/T. I prefer the ChatGPT version, except that I would ask it to include the part about, "Holding the temperature constant gives a much harder to interpret range of energies from 4.2 zeptojoules on the left to 4.0 zJ on the right. Turning those back into temperatures with the normal Boltzmann constant gives 29°C (84°F) to 15°C (59°F)." 172.71.147.19 21:55, 24 September 2024 (UTC)

Yeah I guess I'm dumb since I don't get the explanation either. Is changing the constant basically saying you are changing the definition of a temperature? EG we lowered the constant so 20C is now 30C, thus it's "warmer" (even though functionally the molecules have the same average energy, so nothing actually changed). Or is there more to it than that? 172.68.54.139 20:13, 24 September 2024 (UTC)

On the use of "/" for "or", unless the article has changed significantly since that complaint, it's clearly using the slash in a way that is intended to be a "higher and more localised grammatical priority" than the more wordy conjunction. You might typically say "this slash that" as a monatomic grammatical element which doesn't confuse with wider-scope conjunctions.

"I prefer fish-and-chips to either no fish-and-chips or just fish/chips on their own...", to give an example (with a British slant, sorry; batter-fried fish and (home)fries in a more US context). You have to distinguish the "and"s as not part of the wider grammar (using "&" would work, also) and the slashness of the choice of thing to be on its own needs to not be confused with the either-or "or". (Maybe "...or just fish or chips on their own" might work, but could be read as "just fish" or "individual chips", depending upon how you interpret the plural tense, especially given that "fish" can be "a fish" or "some fish(es)". Whilst "...or just fish, or chips, on their own" hits a problem that "...or just fish, or chips, on its own" might solve, but at the expense of straining grammar in a different way.)

In the article, though, it is "heating/cooling" as an atomic choice of effect (that cross-relate directly with the following "below/above" similar alternates). The implication is that reading the sentence with either option is valid, without writing the whole sentence out twice, each time dedicated to the different singular option involved. This is different from lazily using "/" for a 'full' "or" (and "&" for "and").

Above all, does it aid greater understanding? Yes, I think it does. The mental parsing is less ambiguous. Just like variable1 and variable2||variable3 may be different from variable1&&variable2 or variable3 for {False,<either>,True} input sets, in a coding language that supports both forms of logical operators at different levels of precedence – and avoiding/alleviating thebkind of bracket-soup that it might already be floating within as part of a larger logical assessment.

It's probably intrinsically way more understandable than my above analysis and its analogies! But it's how I read it and my best way of explaining my understanding. 172.70.91.253 06:58, 25 September 2024 (UTC)

Maybe worth noting: this is almost the joke of https://www.xkcd.com/2292/. 172.68.210.15 (talk) 08:52, 25 September 2024 (please sign your comments with ~~~~)

1) Sign, please; 2) May be more handy to internally use something like [[2292: Thermometer]], here, i.e. 2292: Thermometer; 3) Similar basis, but weird/obscure/awkward actual measure, with the necessary constant (for conversion purposes) still being constant.

Randall's clearly well versed in the use, or at least the generalities, of k. I think these are two different jokes(/punchlines) taken from the same root physics. I'm sure there's a good way of noting the link, even if it's not as close as you suggest. 172.70.160.182 10:14, 25 September 2024 (UTC)