the concept of temperature

Teaching thermal physics,
is as easy as a song:
You think you make it simpler,
When you make it slightly wrong!
---Mark Zemansky
If you took a shot every time I say "it's interesting!" during this video you would literally die. So please don't.
Patreon link: / acollierastro

[@JohnBainbridge0]

To truly understand temperature, you have to have a lot of degrees.

[@bmclive3988]

😂

[@alonskii]

Actually... Just one... And yes, I'm fun at parties

[@hamoro96x65]

I guess physicists have 6 jokes now

[@мимокрокодил]

well it is all about the nature of temperature rather than of understending temperature

[@CYXXYC]

of freedom?

[@AdrianColley]

A single atom having temperature 1/0 is my new favourite physics singularity.

[@piratecheese13]

[insert the most obvious black hole joke]

[@matthewtalbot6505]

As I was listening to that, I noticed she used a hydrogen ion as the example. What about a single helium atom? What about the quarks that make up that proton?

[@caesarinchina]

​@@matthewtalbot6505Hellium she basically described when she went into two atoms example. As for quakrs, my gut tells me it wouldn't make sense, since we never see quarks in isolation, due to "color confinment". Meaning, from the perspective of stat. mech., proton or neutron is one, altho it has "parts" (don't get me started on gluons). Ave!

[@suomeaboo]

is it something like asking "what state of matter is a single atom ?"

[@at0mly]

this is a hot topic

[@NealBauer]

( ͡° ͜ʖ ͡°)

[@lex224ification]

* angry upvote *

[@AnnieRegret]

❤

[@mortache]

Or cold topic, because temperature doesn't mean hot

[@ckq]

Cold topic

[@shrededpudding5921]

In the world of refrigeration, we will even measure pressure with thermometers because our systems are closed loop. This means that we are measuring pressure by measuring temperature by measuring a change in voltage in some wire.

[@brandonclark5576]

And in turn, the change in voltage in the wire is caused by a change in temperature at the connection point of two different metals. Mind= blown.

[@ogi22]

You just need to know the amount of your agent. Then you can do it.

[@ShonMardani]

When we look at the "water temperature volume graph", we know that sea level has not increased according to observed science.

[@ogi22]

@@ShonMardani So you are saying that overall globe pressure is rising?

[@ShonMardani]

We know that everything is changing in cycles, but we do not know which cycle or where in the cycle. The fact that we are burning everything that can burn to get energy for our lifestyle will hurt us and our children is not disputable, we all know that and are doing our best to be more efficient with energy. However every number they provide as evidence, is fake and madeup. @@ogi22

[@allanjmcpherson]

I personally love the way we use electron-volts as a unit for practically anything. Energy? Electron-volts. Temperature? Electron-volts. Momentum? Electron-volts. Mass? Electron-volts. It's the perfect unit.

[@ailblentyn]

I prefer the Hz!

[@ChiefBridgeFuser]

​@@ailblentynow!

[@krox477]

Coloumb

[@TheMemesofDestruction]

“You get an eV! And you get an eV!” ^.^

[@AdrianColley]

It's better than the ounce.

[@getjaketospace]

My cousin once stuck a thermometer in a candle and it exploded. So that is not how you measure temperature, I don't think

[@emilyrln]

The thermometer or the candle?

[@ChristopherSadlowski]

​@@emilyrln or both?

[@emilyrln]

@@ChristopherSadlowski Ooh, I like that option XD

[@paolopasini8200]

or his cousin?

[@jellekastelein7316]

@paolopasini8200 cousin It?

[@Treyast]

26:55 I'm a BA undergrad in university right now, and you are making me seriously consider taking some math, chem, and physics courses. I don't know how well I could do, but you have ignited a curiosity in me about the universe that I forgot I had. You shouldn't doubt how good you are at science communication; you made a BA think about taking a math elective.

[@Some_Average_Joe]

It really depends on who's teaching you

[@Virtuous_Rogue]

My school, CU Boulder, throws all its math and science degrees together with its Arts degrees so my biochemistry degree is a BA. The engineering program is in a completely separate school within the university so my chemical engineering degree is a BS. Unrelated to that, I would suggest a chemistry or physics course over a math one if you made it through high school trig and the school will let you. Math classes are horribly designed and I think they cause people to give up on the subject and anything related unnecessarily. I also think science classes can give a much better understanding of the math anyways. I learned to understand more about calculus and logarithms in physical chemistry (split into a semester of calculus based thermodynamics and a semester of quantum physics/chemistry) than I did in any of the pure math classes I had to take for engineering. 3Blue1Brown is a math KZbinr that made a few "essence of" series about various math subjects that covers them in a understanding focused manner instead of the "memorize how to do this type of problem" you get in math classes if you feel the need to learn math before you can do science.

[@haldorasgirson9463]

The more stem classes you include, the more valuable your degree will become. Biggest benefit of stem courses is what they teach about how to interpret and rank the value of data.

[@andrewxc1335]

Differential Equations is my favorite to teach.

[@n16161]

I thoroughly enjoyed all three.

[@saturdaysequalsyouth]

Fascinating. I studied physics in college as part of my engineering degree and I’ve never heard concepts explained so clearly. And no disrespect to my professors, I thought they were good.

[@ma3xiu1]

In my EE degree we didn't really spend much time on thermo. I remember the kinetic theory of gasses, and modelling thermal resistance/conductance as an electric circuit. We probably also talked about some sort of ultraviolet catastrophe, but that was so many years ago...

[@mellertid]

I think that many of these concepts you need to hear several times for the pennies to drop. It could be just me.

[@christinesorensen8050]

@@mellertidMe too lol. But I’m not a physics person. I just think it’s interesting and Angela is quite entertaining as she educates.

[@danamulter]

Shows up for the science, stays for the existential dread

[@aniksamiurrahman6365]

I showed up for the hot nerd girl, stayed for the hot nerd girl.

[@MattMcIrvin]

acollierastro continuing with the greatest hits of "all the things about physics that are way more complex than you thought"

[@MM-vs2et]

Thats 2nd generation science communication for you. Where it used to be "We don't know much about this, but it's cool", now it's "We know a little bit more, and it turns out all we found is how much we actually don't know about this, but it's cool"

[@leonardomarquesbellini]

Which things about physics are ever as simple as we thought? 😂

[@tmign]

My favorite microstate is Rhode Island. But seriously, I can't believe how you keep me engrossed in your hour videos. Usually I get itchy ar 10-15 minutes with other videos. You are an exceptional communicator and I am hooked.

[@cavebeastdemon3631]

I used to work in an oil refinery, We had a huge vessel , about the size of a ten story building. It was full of steam at about 10 PSI. A supervisor asked me to unplug a bleeder valve at the bottom with a rod by opening the bleeder and shoving the rod in the bleeder. I refused. He said it's only ten PSI and decided to do it himself as I cautioned him against it. He opened the bleeder valve and shoved the rod into it. Out came so much steam under massive pressure that he had to jump away and do an elaborate dance to prevent injury. Every one ran away in fear accept me, as I was standing far away already. The entire area was inundated with steam in seconds. This occurred do to the huge volume in the vessel and the tiny opening in the bleeder valve. We had to shut two very large valves in order to isolate the section and wait for the pressure to dissipate before we could shut the valve. .No one was injured.

[@GodSpaghetti]

Hey you can't just drop the story without saying if the supervisor at least acknowledged you were right

[@cavebeastdemon3631]

@@GodSpaghetti NO, he never said anything about it. Too embarrassed I guess.

[@R_S747]

Honestly people who are so stubborn and refuse to listen like this are flat out dangerous. I'm glad no one was hurt.

[@nmh11]

Your dice analogy really blew my mind in relation to entropy! Describing entropy as a set of micro-states that each has a predictable chance of occurring is an excellent way to visualize an unknowable quantum value. it really made the concept clear for me, thank you.

[@old-dave]

Professional science communicator INDEED. The upgrade of inter-scene music with graphics is TOTALLY raising my temperature! You're the BEST Doctor Collier!!

[@Andrewbert109]

Aww fuck yes time to drop everything and learn about motherfuckin temperature

[@fTripleSharp]

Love the enthusiasm! It genuinely brought a smile to my face, so thank you :)

[@AlanCanon2222]

Works for me. I am tired of this motherfuckin' entropy on this motherfuckin' plane.

[@EddieA907]

I know right!

[@sinachiniforoosh]

Great video! I do kinda wanna point out one minor pet peeve of mine as a chemist, which is the widespread notion that Einstein “proved” the existence of atoms. What a proof means outside of logic/mathematics is kinda nebulous, but the framing is a but odd because while physicists were skeptical of the notion of atoms existing, chemists were correctly predicting the arrangement of atoms in molecules in 3D space using essentially nothing but characterization methods (do reaction, separate products, check composition of products, and for products that have the same composition, see if they share physical properties). Van’t Hoff’s discovery of tetrahedral geometry around carbon, Kekule’s famous benzene structure, and the older “radical theory” of chemical structures all happened in the mid to late 1800s, long before Einstein. People talked about molecules’ chirality, the “valence” of different atoms. All before Einstein. And it’s not as though they we’re just making things up alchemy style, their predictions, their logic, etc. were all correct. And their errors weren’t errors in theory, they were errors in measurement. Einstein’s contribution was giving a theoretical method for getting an estimate of the size of molecules an atoms (which in a sense made them “more imaginable”), but his proof presupposes that atoms exist. Which is still very cool, but hardly a “proof”. Of course I don’t expect any physicists to know chemistry history. Or chemist, honestly, it’s not part of any standard curriculum (I only learned all this by watching Yale’s oranic chemistry open course when I was a 20 yo nerd whose soul wasn’t crushed by grad school), but I think in general the fact that the timeline of our understanding of atoms isn’t well-known among physicists or chemists (and people generally assume atoms were proven to exist by physicists) relfects the general belief that physics is more rigorous than chemistry.

[@nussiskate3]

*tempeturr

[@cupajoe99]

so excited to watch this - you’re lowkey one of my favorite youtubers. you make science easy to understand. thank you for what you do

[@bmclive3988]

💯

[@ajs1998]

Was desperate for a 50 minute physics video or rant from someone I like that I hadn't already watched. Thank you for this lol

[@NealBauer]

My roommate in college tried to convince me that things weren't actually hot or cold. Instead, he purported objects were better at adding or removing temperature from other things. Twenty years on, if I wasnt 99% sure he was in a mental institution, I'd definitely forward this video to him. 😅

[@jsbrads1]

Objects have many properties, Thermal Conductivity, Thermal Capacitance and Temperature. Conductivity means it feels hotter than something else even tho they are the same temperature, like metal and stone on a sunny day. People confuse this and think the object is hotter than other objects even when it isn’t. Capacitance generally means if it is hot now, it will stay hot longer than an object with less capacitance all other things being the same.

[@Debrafeem]

@@jsbrads1conductivity is just a form of heat transport, it says nothing about whether something is hot or not. You can conduct heat from a hot or cold piece of metal. The three forms of heat transfer are radiation, conduction, and convection.

[@brianofphobos8862]

Your roommate was basically right. Hot and cold are concepts that relate to how we feel about the temperature. A blizzard is cold because we find it uncomfortable. Boiling water is hot because it can scald us. Really there is only less heat and more heat. Even things at -200 degrees still have heat, just not much.

[@Debrafeem]

We don’t feel temperature, we feel the rate of heat transfer in or out of our body (basically the flux of energy in or out) which in most situations correlates with temperature, but not all. So your friend was right in a way

[@Debrafeem]

Things with a low rate of heat transfer are called insulators. So a blanket keeps you warm by insulating you and lowering your overall rate of heat transfer outward to the environment, and so the heat produced by your body is trapped and keeps you warm, increasing your steady state temperature

[@private1177]

Why are you doing this to me. It's 3:40am. I wanted to sleep, now i have to watch science. And im all up for it.

[@davidgustavsson4000]

You didn't have to get up, could have watched in bed.

[@emilyrln]

As soon as we figure out hypno tapes, you can listen in your sleep! (But there'll have to be an upgrade for sleep-watching things.)

[@m41437]

Don't lie, you did that to yourself. You were already awake at 3:40am

[@NateEngle]

The "atoms don't really exist" people would have been blown away by things like FinFET transistors which involve the deposition of atoms literally one layer thick. And the electron microscope images of them are even more cool.

[@Brendakye2468]

I mean yes, but also things like a boy and his atom are right there too.

[@rayoflight62]

Once I watched a video where there was a layer of atoms from the surface of a silicon block. It was very fun watching them giggling all time. Sometime, at random, some atoms switched places; and where there were impurities (3 or 5 Valence) some epic fights took place; I couldn't see them, but the battles were caused by free electrons. Nature is stupendous...

[@jiffylou98]

Currently in a shit nanoscience class with terrible structure and you have triggered me. I vow revenge on you and the MOSFET cabal

[@NateEngle]

@@rayoflight62 I used to do computer support for a lab when they used an electron microscope to study neurons. Prepping the targets with liquid nitrogen was really important to keep the slides clear - as Angela notes here the thermal energy is all about motion but some people want still photography.

[@aniksamiurrahman6365]

Atoms as their classical sense indeed doesn't exist. In the modern sense tho, its a real wonder what a island of stability Atoms provide.

[@Billy-I-Am-Not]

your point about how the oceans warming up by one degrees is a really bad thing despite "one degree" not seeming like that much of a difference was really poignant to me

[@carlosgaspar8447]

using the relation of pressure to volume (p1/v1=p2/v2), you only need to increase the atmospheric pressure by 3.5% to increase the average temperature by 10 degrees kelvin.

[@BenWS]

I paused the video to calculated the energy required and got about 57 million trinity tests, so yeah.

[@sladewilson9741]

The Ocean temperature off the coast of California about 10 degrees from Summer to Winter. I think your calculations are off.

[@orterves]

​@@sladewilson9741 I think we're talking increase of the global average, right? Fluctuations and variations are expected within any particular part of the constantly-changing system

[@triffid0hunter]

Here's another perspective: It would take 55,546× the world's entire annual electricity generation in 2022 to raise ocean temperatures by 1° - and that's _ignoring_ energy that goes into the ground (incl mountains) www.google.com/search?q=1%2C386%2C000%2C000+cubic+kilometers+*+1+kilogram+per+litre+*+4.184+joules+per+gram+per+kelvin+*+1+kelvin+%2F+29000+terawatt+hours

[@VagueHandWaving]

In statistical mechanics, we do measure temperature in units of energy as well. Boltzmann's constant is just a bookkeeping number like Avogadro's number that tells us we're working with the wrong sized stuff.

[@Trucmuch]

surely you meant SATistical mechanics (31:34)

[@mrhassell]

I often wondered if Faraday’s Constant when put in the same space with the Fine-Structure Constant, would result in the Electric Universe.

[@bruhmoment1835]

@@mrhassellwhat do you mean by space?

[@mrhassell]

@bruhmoment1835 distance between two objects

[@thylacoleonkennedy7]

11:08 It's so frustrating because it's like, "oh it's only one degree!" okay, what's the difference between ice and liquid water? That's right, it's one degree! So if the average global temperature goes up by one degree that means there's going to be a lot more liquid water (I get that it's an average and different areas will respond differently, but you get the point). So then there's going to be a lot more places _under_ water. And unfortunately a lot of those places are going to be small islands with people who can't really afford to just up and move when their houses become flooded. Don't even get me started on the fact that thousands of species use seasonal changes in temperature, humidity, etc. to trigger things like migration, flowering, hibernation, and how much they're going to be screwed up, or the fact that adapting to these changes usually happens over geological timescales.

[@Vaaaaadim]

I wouldn't think of the difference between ice and liquid water as being one degree. The amount of energy it takes to turn ice at 0 degrees C to water at 0 degrees C is the latent heat of fusion (334 joules per gram). Which is different from the amount of energy it takes to turn water at 0 degrees C to water at 1 degree C (4.186 joules per gram), the specific heat.

[@thylacoleonkennedy7]

@@Vaaaaadim that's really interesting! I only did a unit on thermochemistry in my undergrad (in evolutionary biology) so I'm not at all a physicist. Would it still be accurate to say the difference is approximately a single degree for everyday circumstances?

[@Vaaaaadim]

@@thylacoleonkennedy7 I'm not at all a physicist either, I just happened to remember these two facts. Everyday circumstances seems vague to me, I'm not confident to say whether the assumption would lead you astray in everyday circumstances.

[@CycleWerkz]

@@thylacoleonkennedy7 Is a university classroom the only way you know to learn things? I learned this bit in High School. State of Matter changes do involve heat energy transfer. Lots of heat removed to freeze water, lots of heat added to melt ice. A similar heat transfer occurs when liquid water transitions to vapor. This is the overwhelming method of heat transfer from the surface to higher elevations in the air. Water evaporates from ground water, from leaves, water bodies, rain, and even sublimates from snow or ice, even at the poles. This water vapor carries via convection latent heat way up high in the sky, then condenses to make rain which releases this heat before falling back down. The CO2 effect is much much smaller than that. It is however still a factor, but at the existing density, it has no more room to increase it's air heating effect. CO2 does have lots of room to increase crop yield, forest expansion, desert reduction, really a large benefit for every C3 plant, albeit less beneficial for most C4 plants. Did you know we are now in an Ice Age? I learned that in High School too. Ice Ages are by definition times when the poles have ice. This time is known as Glacial Minima or something like that. HS was long ago. There are forests buried under the snow and ice at the poles. How can anyone imagine a warmer climate could be a bad thing? I guess if you hate trees, sure. Just think about how much heat was needed to liquify all that ice. Yet between ice ages life on earth thrived for all organisms. Was this not covered in Evolutionary Biology? If you really want to understand the history of climate, Geology holds the irrefutable information. Or just stop ignoring the obvious. Ocean water temps and levels continue to change along geological timescales. While NOAA has creative ways to make adjustments to their reports, the internet never forgets. You can check for yourself, just pull up NOAA reports published 20-30 years ago, then compare to recent reports. Especially interesting disagreement around the 1930s. And the US Navy Ocean temps reports show little to no Ocean warming since their beginning. And I built a facility in Miami recently, Army Corps of Engineering and a Hydronics Engineering firm we hired both showed very nearly zero rise historically or predicted. The Maldives water levels went down, not up. They added a new airport. They're not exactly poor. The island masses have been rising, that's how islands occur.

[@gcewing]

@@thylacoleonkennedy7 No, because the difference between ice and water is not a matter of temperature. Both ice and water are capable of existing at 0ºC. If you have ice at 0ºC and you put energy into it, it will stay at 0ºC until it is all melted. Only then will the temperature start to rise.

[@thomasfranks7044]

You are a good and intuitive teacher. Thank you

[@billcipher3737]

I love your videos, i feel like physics youtube needs videos just like yours. Chill, almost video essay like, with an interesting personality. Keep going!!

[@JohnBerry-q1h]

I used to work for the Eurotherm Corporation. What I always thought was interesting about the two-dissimilar-metals Thermocouples is that, no matter HOW LONG the overall length of the two conjoined wires (whether the length be 6-inches or 16 feet), the voltage measured across the two conjoined wires, for any overall length, will always be the same (if the temperature at the union-of-wires point remains constant.)

[@jolioding_2253]

one thing that should be said regarding diatomic gasses and their heat capacity is that the additional degrees of freedom are mostly frozen in the ground state which is typically around room temp. So assuming ideal gas behaviour works for those gasses too in a certain range. And the same applies to solids; the colder it gets the more degrees of freedom are frozen and so a materials heat capacity sinks with temperature to the point where at almost 0K even the most miniscule addition of heat will raise the temperature again and increase the heat capacity.

[@SpecialEDy]

Its intuitive for me dealing with speed of sound. The speed of sound is affected only by composition and temperature, not pressure as you might first think. So temperature is the relative speed that molecules are bouncing around. A sound wave propagating through a fluid or gas travels at the speed that the molecules are moving at.

[@Wepper1]

I love the fact that I'm not the only one that accepts that pV=nRT is the best equation of all time

[@АндрейДенькевич]

It show connection between 2 lines: "space-time" and "DOF-LTE" . (DOF -degree of freedom; LTE - local termal equilibrium).

[@ps.2]

Always takes me back decades to Froshchem where I first heard the line "volume times the pressure, nRT" sung to the tune of "there will be an answer, let it be." I will never ever forget that equation, even if for some reason I stop encountering pressurized gases in the real world to remind me of the idea.

[@marekful]

It's absolutely brilliant how you drew the analogy with the two dice and distribution of combinations. It's a helpful addition in my multiple year long journey in trying to understand entropy without being a physicist.

[@rayoflight62]

Transducers are electronic devices that transduce a physical or chemical entity into an electric measurement. Body thermometers use an 10 kΩ NTC (negative temperature coefficient) resistor. In some cheap thermometers you can find a silicon diode. Silicon has a bandgap voltage of 0.68 V which varies exactly -2 mV/°C.

[@stevenklinden]

The stat mech problem on my qualifying exam in grad school involved negative temperature, and I think this is the only thing I remember about my qualifying exam in grad school.

[@aldohorn1704]

I'm a linguist and everytime science people (physics and biology type science people) look up dictionary definitions I have the same reaction. Them: *Reads definition* Me: Yeah that's pretty good. Them: But this isn't really useful. Me: 👁👄👁

[@iccuwarn1781]

Great video as always! Love the music choice :) Here’s a real-world example of how to create negative temperatures using magnetic fields: Take a sample of solid Lithium Fluoride and put it in a strong magnetic field to magnetize it. Lithium Fluoride is used for two reasons: first, the Lithium nuclei behave like paramagnets so they can be easily magnetized. Second, the Lithium nuclei are poorly coupled to the rest of the crystal so it takes a long time for them to demagnetize on their own, giving us a chance to measure the magnetization. Let’s define it so that the magnetic field is pointing “up” and the field is so strong that it has aligned most of the spins of the Lithium nuclei. To work with some numbers let’s say that the field is so strong that 80% of the spins are aligned parallel with the field pointing “up”. The remaining 20% of Lithium nuclei spins are pointing “down”. Referring to Dr. Colliers graph at 40:20, we would be on the left hand side of the graph because most of the spins are pointing “up”. To get to the right hand side of the curve where the slope of ds/du is negative, and therefore the temperature is negative, we have to flip the spins so most are pointing down. To do this, the sample is quickly removed from the strong magnetic field and placed in a solenoid (a hollow cylinder with wire wrapped around). Through the wire we short circuit a current creating a magnetic field in the solenoid and our sample that only lasts a few microseconds and is pointing “down”. This brief field inverts the spins of the Lithium nuclei so that now, 80% of the spins are pointing “down” while the remaining 20% are pointing “up”. If the sample was originally at room temperature or roughly 300K while saturated in the strong magnetic field, the spins of the lithium nuclei now correspond to a temperature of -300K. The rest of the sample, that is the Fluoride atoms and electrons, is still at room temperature, so the way we measure this negative temperature is by measuring the size and direction of the magnetization of the Lithium atoms. This can be done for instance with a radio frequency spectrometer. If you’d like to know more, the experiment I just described was first done by Purcell and Pound and published in Physical Review 81, 279 (1951) “A Nuclear Spin System at Negative Temperature”.

[@mrhassell]

Likewise, heat can also be created from magnets by putting magnetic material into a high-frequency oscillating magnetic field that makes the magnet’s polarity switch back and forth at a high-enough rate to produce noticeable friction.

[@Brendakye2468]

"You'll hit the backboard, sports" A yes, I too am very knowledgeable of sports where you score points and there are balls and players on teams.

[@ps.2]

Imagine a spherical game ball....

[@idontwantahandlethough]

You did a really great job explaining this! I've always been a little confused about the topic of temperature and you definitely helped clarify some things, so thank you :)

[@BenWS]

41:44 Maaan why you gotta be like that to my boy negative temperature? Here's a few things about negative that I think are super cool: The derivative at the crossover point is zero, which means the crossover is through infinite temperature. It's pretty rare to be able to push past infinity in physics. Negative temperature doesn't make any sense for classical systems but works perfectly with quantum quantum quantum. That's a cool little feather in Stat Mech's cap and also makes it one of the few pieces of quantum weirdness that I've never seen grifters try to co-opt. Every (N)MRI scan involves population inversion into negative spin temperatures, must one more thing that makes (N)MRIs cool. I just found your channel recently and I'm really appreciating your videos, thank you for making them!

[@meistersuperbatman2865]

Can you recommend som watching or reading o the MRU topic? Because I was interested on how they work on a physical level but most information I found in media was not that ‘deep‘.

[@BenWS]

@@meistersuperbatman2865 I'm sorry, I can't. All of my knowledge of MRI comes from pop science media or graduate textbooks and journal articles about NMR from when I was doing some NMR experiments. The truth is that it's mostly interesting because you learn about negative temperatures in stat mech and at first it seems like a completely esoteric thing, like just a trick of the math that doesn't mean anything, but then you find out that every modern MRI scan involves population inversion from positive to negative spin temps and negative temperatures can happen all the time with quantum quantum quantum. I'm also joking around because the video is totally right and negative temperatures really are not particularly useful. The spin temperature of the hydrogen nuclei in an MRI might be negative a million kelvin but that's just the nuclear spin population, the system as a whole is still room temperature. It's mostly just a fun thing people working on high power NMR or hyperpolarized gasses will calculate as a piece of trivia (ex: "by the way this system is technically at negative two million Kelvin for this step") but since you have to determine a bunch of other, much more useful, aspects of the system to make that calculation I'm not aware of any real reason to calculate these temperatures beyond it being kind of neat.

[@ps.2]

A discontinuity between positive and negative infinity doesn't seem strange to me at all. Isn't that just what _tan θ_ looks like?

[@keithl3789]

Had to do some research to figure out what you were referring to... For others.. temp can be defined as derivative of energy wrt entropy. That derivative goes to infinity, thus the "passing through infinity" for temp. Whereas the derivative of the inverse is zero.

[@keithl3789]

And you can easily "pass through infinity" for anything if you redefine units. For example reversing direction makes inverse velocity "pass through infinity".

[@me0101001000]

This was a fun way to help me make sense of more of my thermodynamics and kinetics concepts for my comp exam. Thanks, Angela!

[@praecorloth]

11:20 "Do you realize how much energy it takes to raise the temperature of the ocean just 1 degree?" This has always struck me as strange. I'm a computer nerd, myself. I've done a ton of security work, and among that work has been password cracking. And people on forums would often talk about the crackability of various lengths of passwords and hashing algorithms and whatever else. But the most common phrase you'd hear saying that it wasn't feasible to crack something was, "The amount of energy needed to crack this password would be enough to boil all of the water on Earth." Like, we're doing it! We're starting the process of boiling all of the water on Earth! How can anyone be calm about this?! People suck.

[@gcewing]

Ah, so climate change is happening because someone somewhere is trying to crack a really hard password...

[@fluffy_tail4365]

To be fair we're more allowing the sun to boil all the water. Which is not much better for the outcome but also it means if our energy budget keeps growing we'll arrive at the point where our own waste heat will also chime in

[@bernhardschmalhofer855]

Actually there is no danger that the oceans are boiling off. But the known effects of global warming are bad enough.

[@praecorloth]

@@bernhardschmalhofer855 no I know there is no real danger of actually boiling off all of the water. It's just amazing that people seem to understand the energy required to bring a certain amount of water to boil, and yet the fact that we've brought the oceans up a degree doesn't seem to bother an irritatingly large number of people.

[@hayuseen6683]

Anything bigger or more distant than humans' normal perception is difficult to relate to. We understand a hot cup of coffee, we can't understand an ocean's worth of water. Same thing for planning hundreds of years for an ecosystem rather than for next business quarter. That and there is a LOT of motivated reasoning to deflect the conversation so that the golden age of industry can continue indefinitely when it's running out of road. ​@@praecorloth

[@zotriczaoh7098]

What a great talk. Thank you so much. I've studied this stuff a bit over the years but never seen anything so succinct and rivetting. It is highly probable that I'll watch it again. Probabilistically speaking.

[@lunasophia9002]

35:20 "just vibing at some energy level" I see what you did there

[@snared_]

"some" meaning 10^100 ^_^ vibing at 10^100^...tetrated^100

[@LabMuffinBeautyScience]

Loved this video, I dropped high school physics for petty historical reasons but I loved upper undergrad physical chemistry so this felt like filling an incomplete skill tree. Don't know if this will be useful to anyone, but I was head of chemistry at a tutoring college when the syllabus changed and we started teaching entropy to 15-17 year olds in the context of spontaneity, G=H-TS etc. The qualitative definition that's been working pretty well for the last 5 years for us is "a measure of dispersal of available energy (more ways of distributing energy = higher entropy)" - we found that "disorder" was tricky for things like a glass of liquid water vs a glass of ice cubes, since intuitively ice seems more ordered, but "dispersal of available energy" is flexible enough to encompass both microstates and disorder (since most schools still teach "disorder"). There's a bunch of Chem Ed articles from Frank Lambert on this that are really interesting!

[@fmdj]

this is giving me the chills already at the intro

[@EddieA907]

Dr Collier another lesson. What a wonderful surprise. Your insight and knowledge is always a pleasure to watch.

[@DrStanky]

-40F 🤝 -40C

[@TheAnticorporatist]

Yup

[@OhhCrapGuy]

​@@polusdroop 0K == 0R

[@anon69_q]

@@polusdroop bruh

[@PineappleForFun]

In terms of symmetry the one about when exposed flesh freezes is also pretty satisfying, albeit it's all fahrenheit. At -30F you have 60 seconds, at -60F it's 30 seconds.

[@qsvui]

@@polusdroopackshually it's just kelvin not degrees kelvin 🤓

[@gregstarr2]

Wow great demo and filmed very clearly too

[@Virtuous_Rogue]

Two minutes into the video and I realized I have a chemical engineering degree and never directly questioned or analyzed what temperature was. We got hints at it in P Chem but temperature is such a fundamental concept that we ignored it by that point. It's like learning 1+1=2 in math and never addressing why that's the case if you aren't doing a math PhD. It does become intuitive that temperature is not heat and is not energy, especially kinetic energy but a definitional look at temperature after learning how all this works is fascinating. Latent heat has a whole new weirdness to me because you're adding kinetic energy without increasing temperature. (For people reading this who don't know what latent heat is (can't remember if Angela addressed it), it is the heat you have to add to a substance to cause a change in state. More practically, it's the scientific concept that boiling water happens at a constant temperature.)

[@ShonMardani]

When we look at the "water temperature volume graph", we know that sea level has not increased according to observed science.

[@Virtuous_Rogue]

@@ShonMardani You haven't been clear about what you are criticizing so I'll cover each topic you get at. 1) Liquid water basically doesn't expand with temperature but that has never been the main cause of sea level rise. 1.5) Sea level rise: Water froze on land (Greenland, Antarctica) thousands of years ago. That is what is melting, that is what is raising sea levels. Less sea ice is considered a problem because ice is white and reflects light (energy) back to space. Less energy reflected means more energy sticking around here. 2) Increased energy in the atmosphere is a huge concern because it's making the climate weird. It rained in Colorado in December. Good thing Colorado doesn't get hurricanes. And if the climate changes, the great plains could become a second Sahara, or a rainforest, or a swamp. We don't really know other than changing what has been there makes it likely there won't be plains there in the future.

[@ShonMardani]

Every experiment showed that basically water expands with increased temp. Multiply the volume of the ice by 0.92 to get the volume of water from its melt. Also there are a lot of air bubbles and solids which will be released and reduce the volume of melted water. Everyone agrees that the climate has been changing way before we had cars and power plants. We know that everything is changing in cycles, but we do not know which cycle or where in the cycle. The fact that we are burning everything that can burn to get energy for our lifestyle will hurt us and our children is not disputable, we all know that and are doing our best to be more efficient with energy. However every number they provide as evidence, is fake and made up. @@Virtuous_Rogue

[@marc-andrebrunet5386]

📌I understand more the physics world because of the way you explained science stuff 🤘😎 thanks for what you do in the communication world. Today I learned how my electronic thermometer works ! ✔️🤩 Temperatures is more complicated than I thought..but because of your video, I did learned a little bit more about this awesome subject.. By the way, my name is on Parker solar probe 🤘😎

[@TweenkPL]

16:15 The motions away and toward each other are actually the same vibration mode, but there are two degrees of freedom per mode, one each for kinetic and potential energy.

[@hicetnunc1129]

Was going to write this, then thought I'd better check whether someone else had already commented this. It also isn't trivial that there isn't a third rotational degree of freedom for diatomic molecules, but most books skip over this and I don't really understand it either (some QM reasoning) so "it's fine".

[@АндрейДенькевич]

i think that there isn't first rotational degree of freedom visible in space. Circular DC is a electric mass (dof=2) Electric amplitude ,charge (dof=1) For example, take Carno's cycle on dof-lte line (electric). And apply it to space-time line (magnetic) then: D->A is iso-time decompression of space (1d-> 2d in 0 second) A->B is iso-space decompression of time (time begins flow in 2d) likewise C 1d in 0 second) D

[@danielhady3021]

I work in the power industry as an operator and electrician. This was a lot of fun listening to, because the ways processes are measured with instrumentation is indeed very interesting. Your explanation of RTDs and thernocouples were spot on. Its really interesting all the different ways we can measure pressure, temperature, and flow.

[@dougthomson5544]

Lord I wish I had you for a physics and/or math teacher so long ago, Angela. You are very interesting.

[@paathimself]

Crash Overdrive sighting. (I had my copy signed! Real nice lady) Your content has been super-resonating with me from the science to academia content. (I made the mistake of being too afraid to go to Try 1 of 2 of my qualifiers, almost passed Try 2, all nighter, crash and burn on the oral exam). Now I’m an MS and MEd, teaching AP Physics in HS. No regrets in hindsight because it’s been 14 years, but your “no one told me this about academia” was just SO on point. Actually I think I want to try for phd again in 19 years when I retire to avenge myself. We’ll see if I still feel that way then! Thanks for the videos, prof

[@jamesdriscoll_tmp1515]

I came here for a quantum of quantum quantum quantum, And I left with the average of all of them.

[@GeoffryGifari]

Wait... at 28:21 when you remove the partition, if _the bigger box didn't contain matter_ wouldn't expansion occur at constant temperature (isothermal expansion), because the expanding gas is not pushing anything, not losing kinetic energy? With the average kinetic energy they had the molecules just able to move further

[@potato.pancake]

i watch these videos to keep my brain stimulated as i’m knitting. 10/10 recommend.

[@mrhassell]

Having 8 thumbs and 2 trunks attached to meat cleavers for hands, hasn't equipped me with the dexterity for knitting... although, I play guitar and piano?

[@OddHominum]

I love these concept breakdowns!!! I just rewatched “Mass” because it’s so informative

[@glarynth]

You joke about "professional science communicator," but it would be a great victory for popular science if mainstream media could compare the physicsicity of the various physicses.

[@induspherix]

Noice! The dice roll analysis applied to conceptualize macrostates and microstates is marvelous. I am in awe that I have only now been exposed to this model for a descriptive grasp of how temp observation interprets particle kinetics and distribution a la gas laws, beyond my complacent comfort with an intuitive understanding of average kinetic energy (borderline vibe awareness). Same goes for upping my self-awareness in the entropy discussion, naturally. I must have missed a primer long ago, because I am over 3x older than I was when I learned the word permutation and tuned into the entropy discourse as a student of chemistry. This includes multiple sections of physics prerequisites+ and a continuing interest to develop critical thought to explain entropy ever since. I was never too confused by most prior explanations, except I usually felt like I kept coming up short on how I could convey the practical examples to not-particle-physicists without a conceptual leap that probably sounds like a tortured metaphor from o.g. Star Trek to my more neuro-typical friends 🤖

[@JH4mm3r]

After a sad session of sifting through a bunch of marketing vloggers disguised as "girl programmer/scientists" it is so reassuring and comforting to come across this video. Thank you for the quality content!

[@bitodd]

Can you believe the nerve of those other women, trying to find a way they can get involved in STEM? “Not you. You’re one of the good ones” isn’t the compliment you appear to think it is.

[@movement2contact]

​@@bitoddWhere's the list of all the one's he watched?

[@JH4mm3r]

​@@bitodd I'm specifically talking about frauds who know they are frauds with fake professional titles masquerading as "girl scientists" for marketing purposes. Their production quality is actually very high and there are a ton of men doing the same thing pretending to be software engineers. I don't want to call anyone out in particular but before I posted this I had come across a few particularly misleading marketers with lofty titles trying to sell pink keyboards, mouse pads, organization software, gaming/chairs, etc. I scanned through all of their videos looking for anything with scientific substance and there was literally nothing. Nothing to even be wrong about! Those types of videos do more harm than good imo. This content here is very high quality and it would be ridiculous to hold anyone to this standard.

[@bruhmoment1835]

@@bitodd so grifting is a way to 'get involved' in STEM? Please stay out.

[@CurtOntheRadio]

You successfully convinced me I have absolutely no idea about anything to do with temperature. Well done!

[@Ziraya0]

"it says I'm 90.1 degrees, which feels wrong" This is a really interesting brainworm I'm fostering lately, it is really hard to correctly measure the temperature of a thing, via infrared light, and unless they are designed to deal with flesh, they are particularly bad at measuring the temperature of flesh. I've got one here, I point it in my mouth, my mouth is 94.1 degrees, which is wrong. If you get into the manual for your gizmo you will probably find that it has a setting for Emissivity, which is an adjustment factor that goes into the math somewhere to deal with the fact that real objects are not black body radiators. So before when I measured my mouth, I had the emissivity set to 0.94. Point it at the same spot, but a different angle, now I'm 98.1 degrees. Drop it to 0.90, now I'm 100 degrees. I could tune the measurement angle and emissivity all day and then it would give me a number that agrees with my contact thermometer, but it would also be wrong for my cast iron pan and my 3D printer. Because non-contact thermometers suffer from perception. They can perceive incorrectly, and perception is contextual. Both the subject and the perspective modify what is perceived. There's also a factor that it's challenging to measure infrared light accurately so, this all works better for hot hot stars or if you have very expensive equipment, which may need to be cryogenic. These fancy laser pointers with eyes rely entirely on the operator to manage the factors on perception. Flesh, cast iron, and stainless steel all have different challenges because: Flesh is not opaque at infrared wavelengths, meaning when you point it at your wrist you're measuring the surface, which is cooler, and also the blood, the muscle, and maybe the bone, proportionally, but the bones are opaque so they're also blocking the light from the far side of the wrist. Cast iron is maybe the closest to a black body radiator; so much closer that a more generally appropriate emissivity setting is very wrong for cast iron. Stainless steal meanwhile is the opposite, it radiates energy outwards more coherently, so looking at it from a single perspective tends to read the material itself low because you're not getting an even scattering from the whole surface, parts with a surface normal towards you cast more of their IR towards you while other parts cast less, and it reflects IR from the room so like the hand being a proportional combination of all the layers of flesh, the pan is a proportional combination of nearby objects and a non-generalized perspective of itself. Which is all to say that in the kitchen, these devices are primarily misleading, and in medical applications only the ones designed for the job and used as intended, can produce meaningful results

[@ps.2]

I've wondered lately: how does an infrared thermometer pick the photon to report, anyway? Does it just pick the one with the shortest wavelength (within a certain design range of the instrument) from within some small angle of the direction it's pointing? Does it do some kind of averaging or weighted averaging?

[@Ziraya0]

​@@ps.2 any half decent IR thermometer will be marked with the parameters of a cone*, it reads a wider area the further away you are. Mine is 38mm diameter at 300mm, 75mm at 900mm, and 132mm at 1 meter, which may not legally qualify as a cone. I don't really know the shape of data these sensors put out and that's going to dictate most of how they can determine what temperature the reading indicates.

[@mrhassell]

Special Relativity is applicable to thermal systems, but it introduces complexities. The integration of thermodynamics with Special Relativity is a topic of ongoing debate and research. As you point out, the temperature of a moving object can appear different to observers in different inertial frames. This is because the relativistic Doppler effect influences the observed temperature. Additionally, the Zeroth Law of Thermodynamics, states that when two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other, and need to be redefined in a relativistic framework to account for the relative motion of the systems. This currently (afaik) remains a “perpetual problem”, with four different attitudes, having been famously expressed since 1907. December 2, 2020 - Joseph Henry Laboratories, Princeton University - "Temperature and Special Relativity" by Kirk T. McDonald, delves in deeper but there are many other papers and areas of research focused in the area, providing very interesting concepts and ideas (worth investigation).

[@GeoffryGifari]

Hmmm thinking about 33:29 If I were to have cream and coffee (both solutions, with fixed number of molecules and fixed volume) with the _same temperature_ First I separate them into layers Then I let them mix strictly via diffusion How would the temperature change after the solution reaches equilibrium?

[@RedPandaLesbian]

Back when my parents used to live in North Carolina I used to pass a place called Isothermal Community College on my way to visit them and I always thought a good slogan for that school would be "We stay cool under pressure"........

[@reis5011]

funny that the microstates-macrostates concept was explained to me in grade 10 biology to explain why concentration gradients were a thing. that was the FIRST time entropy made any sense at all in my head and im shocked that it is actually pretty solid explanation and not another one of those hand wavey definitions we get pre university

[@jeffmiller6954]

An interesting topic which I believe is completely understood today but in 1800 there were still some people who thought heat was a substances. Moreover, I am not sure that "cold" was understood as the absence of heat but something else. I can recall being 5 years old and my dad bending a coat hanger to make a primitive tool and I was amazed that the metal got quite hot. He said, "Heat is motion." A revelation to my five-year-old mind for sure.

[@hedgehog3180]

The leading theory going into the 19th century was the caloric theory, it was only decisively abandoned with Boltzmann's Statistical Mechanics since that finally gave a clear theoretical understanding of what it meant for heat to be motion.

[@ConsecDesign]

your audio and video quality is so much better lately. it really makes a huge difference

[@inappropriatejohnson]

Thanks for pointing out that pumping 40 billion tonnes of carbon out of the ground every year and dumping it into the sky will eventually change the sky for the worse. I have found that treating religious conservatives like children sometimes gets through. Sometimes.

[@Some_Average_Joe]

Up until they hit you with "God wouldn't let that happen"

[@jkevo16]

At a point yes but all that CO2 has been a net positive so far.

[@inappropriatejohnson]

@@jkevo16 Dear Lidiot (liar + idiot) J, you should not get your science info from Prager-U vids, for they are made by morons for morons. And don't troll comments made by anyone named "inappropriate". Now go back to school and try harder this time. This is an actual science channel.

[@hedgehog3180]

@@jkevo16 Yes the problem is that we still have net positive emissions right now.

[@Some_Average_Joe]

@@jkevo16lol, wut?

[@CasperLCat]

The frequency diagram with the dice combinations is pure gold, as a learning tool. It speaks to probability, Entropy, frequency distributions, combinatorics, etc. Gold, Jerry, gold !

[@815TypeSirius]

COLLIER TIME BABES

[@bainides]

boss bossy boss babes

[@bradley1995]

What a lovely way to start my day! The thing that gets my mind is the fact with the meat thermometer or body one. Like how does are body effect the voltage/resistance due to us being sick or under the weather. Its like you could hook up to a machine and measure each organ, and almost know the status of it based on the measurements taken. Absolutely amazing to learn. The fact you make it understandable to a pretty self taught guy like myself, cheers!

[@howwitty]

It's about to be vibrating molecule boy summer. Google says 5.43 × 10^21 kJ will raise the temperature of the ocean by 1° C.

[@OhhCrapGuy]

Gonna go run the calculations manually , curious if I get a similar value.

[@OhhCrapGuy]

I got 5.59284×10^21 kJ... So yeah. To put that amount of energy in context: Tsar Bomba was the largest nuclear weapon in history, which released 2.5*10^14 kJ. At the height of the Cold War, there were an estimated 70,000 nuclear weapons total across the entire planet. (7*10^4). The amount of extra heat in the oceans is on the scale of taking every nuclear weapon at the peak of the Cold War, turning them into the most powerful nuke ever constructed, and then detonating them all. 300 times. Or to put it another way, 20,000,000 Tsar Bombas. I don't think that counts as "in perspective"... I don't think this is something that can be.

[@howwitty]

@@OhhCrapGuyHow did you calculate the volume of the ocean, as a proportion of surface area?

[@OhhCrapGuy]

@@howwitty I simply looked up the volume of the ocean

[@xponen]

The actual increase in temperature is likely to be significantly higher due to uneven mixing, similar to how El Niño and La Niña dramatically affect the Pacific Ocean's temperature.

[@xylo5750]

FYI - I love the font choice / aesthetic of this video. I think your channel could do with some more consistent theming, and IMO this font is perfect! :)

[@The_Real_Quantum]

New acollierastro video dropped 🗣🗣🗣

[@fmdj]

and 50m (+50s), she did not disappoint, as always

[@Tribecasoothsayer]

This Saturday, is THE Saturday

[@Aurochs330]

All i ever knew about it was how 'particles' vibrate and the faster they vibrate the 'hotter' something is. the vibrations from hot particles will 'excite' colder surrounding particles thus warming the surrounding particles and cooling down the source of heat. There is so much more to it and you did a great job of spoonfeeding me more nuanced definitions and ideas

[@logtothebase2]

At university, we used to have a big Physical Chemistry lecture and /or tutorial at the end of the week, I always thought, thank god it's Faraday.

[@0o0ification]

I hadn't really considered the challenges of taking temperature, let alone at the molecular level, but I believe that your build-up and description of the challenges in capturing the temperature of plasma was fantastically exemplary, not to mention newly informative. It seems that there is still so much more to learn about the state of plasma before the elementary data of temperature can be reliably recorded by physical experimentation into the same. TIL Thank you

[@djsmeguk]

11:30 holy fuck, that perspective on climate change. 🤯

[@Trucmuch]

Yep that's 5e24 J which is waaaaaay more than all the nuclear bombs ever created combined!

[@mrhassell]

@@Trucmuch In Orders of Magnitude (energy), the Earth receives about 5e24 J of energy from the Sun per year.

[@trickvro]

I like the use of The Science Asylum's music in this video. That really amused me. 😄 I'm sure it's generally available royalty-free music, but it's indelibly associated with The Science Asylum in my head.

[@jimsvideos7201]

Me: whisper those three words and I'm yours forever Her: traceable to NIST Me: 🥺😮🤩

[@Kakaze1]

My statistical physics class was just ridiculous. First question of the first question of the first homework required us to derive the general form of the volume of an n-ball. The goal of that question was to make us figure out how to gaussian integrals because it turns out that this trick comes up pretty often in statistical physics. One of the most difficult classes I took. It's the same class where had to figure out how to derive the gamma function, the stirling approximation, and so much more. I'm an old geezer, so no wikipedia for me to look this stuff up. Sink or swim!

[@dogspaghetti7118]

The legit look of concern on her face at 11:34 made me quiver in my boots :(

[@trickvro]

Yeah, that part was a big oof. 🙁

[@todhagan2966]

Yay, another great video on an interesting and comprehendible subject! Two things: First, you really _don't_ want a mercury thermometer. They're fragile and when you break one then you have to deal with a mercury spill. I speak from personal experience. Second, all through the video I was thinking that the ice melting demonstration could be better. Most of the time the view of the ice was blocked and then when you showed the ice it was so far away that it was hard to see. Finally at the very end you used a close shot that was very satisfying. I think it would have been much better to set up a second camera showing a close shot of the ice and put that frame in a corner of the screen for a continuous view.

[@IstasPumaNevada]

I remember my aunt telling me how when young she and her friends would break thermometers and then play with the "little silver ball" that came out of it. ...Come to think of it that might help explain some of the ways she acted.

[@brucegoodwin634]

Snarky, pithy, educated, and genuine. Angela rocks my phyeek world.

[@mbengaful]

And supercute to boot, it's not fair.

[@UntouchableGlory]

I'm in an environmental science graduate program and that mental whiplash around 11:40 is just how all of us get through the days :D

[@TakeyMcTaker]

Things I never thought I'd hear Angela say [SPOILERS]: "they do the butt one if you're unconscious"..."you can't just shove a thermistor in there!"

[@mrhassell]

Yet, it has been done before and will be done again.

[@Hansengineering]

One of the cooler observations I've encountered with temperature is using a laser/infrared thermometer around the house and in the kitchen. Aluminum beverage cans always show around 74° regardless of the temperature of the contents.

[@jaidei4732]

Old Physics teacher here. The demo with the ice and black blocks is not explained correctly. The metal block melts the ice faster because it has a higher thermal conductivity. It actually has a lower heat capacity than the other block. It transfers heat from itself to the ice and from the environment through itself to the ice because it is very thermally conductive. Because of its lower heat capacity the metal block becomes much colder than the insulating block.

[@jasonjd84]

kzbin.info/www/bejne/rXOln5mrbbOSgJI

[@ogi22]

This is something so difficult to explain to many people - why metal feels cold when you touch it and why styrofoam feels so warm to the touch :) I'm just at the beginning 4 mins of this clip and I sense a bit of a problem. She does a wonderful math, but I feel a bit of a hole where should be that passion for "figuring things out". Sorry, perheaps I like Feynman too much. He was so happy about understanding how things work. Math was just a language you can describe the fenomenon. Understanding it to the point of "feeling" was the main Feynman's goal. And having fun 😁

[@GeekProdigyGuy]

Good point. One nitpick: Heat capacity and conductivity aren't necessarily related.

[@richardv.2475]

​@@ogi22 The strange thing is when ordinary people are talking about Feynman, they always say things like "he had a very relatable street smart way to solve hard problems easily and he was such a relatable teacher, not the typical nerd weirdo" and when professionals are talking about Feynman, they always say things like "geez, that bastard used calculus ten times faster than me". For example Dyson, the mathematical prodigy was very diligent in becoming an early doyen of QED to make his way to the Nobel but Feynman simply outcalculated him. Somehow Feynman's almost unfathomable strength remains unnoticed by bystanders. So watching him is like watching an olympic gymnast on the rings, or watching a world class chess player - although the moves they make look natural and trivial and they are working for them, they won't always work for mere mortals.

[@ogi22]

@@richardv.2475 A "street smart" is just as smart as the street it comes from... And if you talk about the mind, Feynman was from "up-town" 😏 He did one thing with a very little effort. Something all engineers and physicist (and many more) strive to achieve. Quick estimation. There are many tricks to do it. You even have jokes about a physicist drawing a circle and saying "let's assume this is a cow" (a beautiful lecture by Lawrence Krauss "A secret life of a physicist" would be a wonderful example). Even in his books, there are many examples where he is sharing his secret. The problem is, this is "an estimation" and you have to know how and why you did it this way, to know the outcome is plausible. It takes quite a vast knowledge to do it precisely enough. But the first step is to take that calculation and do it, if you feel something is not right. And that's the hardest part 😁 Personally, I try to do it myself. Yes, it's sometimes hard to take out that small notebook from my pocket and write down a few numbers. But the satisfaction after you catch a problem is amazing. Everyone has those "this doesn't compute" moments. Just most people lay it off. Leave it to others. I preffer if my curiosity wins, I open that notebook and check stuff for myself.

[@brodyjohnstancliff4822]

That's an interesting difference in our pedagogy! My MechE education left me with a really different list of speculative answers to your rhetorical "who are the two main guys in thermodynamics" question. I would've been guessing all day before I got to those two: Lord Kelvin? Rankine? Sadi Carnot? Otto? ... Diesel? 😅

[@petevance422]

PV=nRT enjoyers unite

[@mrhassell]

Non-ideal gas law in crowded elevators PU=f** ...

[@JulianDanzerHAL9001]

38:30 and thats where, at least in large scale flwo dynamics you often see a concvept of turbulence that is treated almost similar to temperature as in a chaotic motion smaller than the scale we're looking at but still larger than molecular scale, not to be confused with turbulence at the scale we're looking at which is jsut angualr momentum

[@mynameisrick]

i just watched oppenheimer, you're also a physicist

[@michaeljburt]

Kinetic theory of gases - the starting point for statistical mechanics. I like it. Nice video.

[@BoostlessJoe]

my alien friend Denzel doesn't feel temperature

[@mastersquinch]

if it's hot we use a smaller garment. If it's cold, it's like, a heavier garment to keep me warm.

[@mrhassell]

Sounds like a really chilled out dude.

[@BeorTheOld]

The intuitive way to understand thermodynamic entropy is that, analogous to work performed by/on a cylinder being the integral of PdV, the work done by heat transfer on a system is the integral of TdS. All mechanical losses eventually end up as heat anyway, so as efficiency drops, entropy rises.

[@afroohar]

Wait acolier I love your videos but you made a big mistake in this one (16:30). The average KINETIC energy of ANY (classical) substance is 3/2 N kBT, where N is number of atoms. You can derive this from the Boltzmann distribution for a classical system of N atoms with an arbitrary potential energy. The momentum integrals always factor out. What you’re thinking of the average TOTAL energy, which contains an extra factor due to vibrational interaction. For a diatomic gas the average KE is 3kBT and average total E is 7/2 kBT. Additional 1/2 comes from integrating over position degrees of freedom.

[@De2Venner]

Can you measure one without including the other? For all practical purposes they are kinetic degrees of freedom right? They can reasonably be approximated as quadratic degrees of freedom, so we can use the equipartition theorem. It’s not like strong interactions where we have to deal with it separately.

[@afroohar]

​@@De2Venner 1) Only for solids gases/solids can they be reasonably approximated as quadratic, for liquids, glasses, biological systems, etc. they cannot. 2) Quadratic =/= Kinetic. 3) The distinction is actually important for how we determine the temperature of simulations of complex anharmonic systems.

[@De2Venner]

@@afroohar Interesting, thank you for the answer. I will not argue semantics about the second point, it seems very meaningless to me. I will however say that I have not encountered a quadratic degree of freedom which did not have associated with it a quasiparticle that moves with such a "kinetic" energy. so call it what you will as long as you agree it can be interpreted as such. For 3) I'll admit that I haven't thought about how to determine the temperature of a many-body simulation before. Its definition is rooted in entropy/heat, which is hard to define for a system where you know all the microscopic variables already, so I imagine it is quite difficult. I guess you need to consider the modes which can transfer energy across large length scales, such as the kinetic energy, vibrational modes in a solid, etc. Seems cool honestly, good luck on your research since it seems like you are working in a related field c:

[@marmoth9786]

it's been a few years since i barely passed high school physics so i understand about 15% of the proof, but i love listening to you talk

[@maximuscesar]

Never saw anyone explain global warming like that. Makes it much easier to visualize (and also much more scary 😰)

[@hedgehog3180]

Don't forget that this goes along with ocean acidification, the oceans have been absorbing most of our carbon emissions so far, which is why it took a while before temperaturs started rising, however that has produced carbonic acid. Since the oceans are more acidic that means more calcium can be dissolved in them, which makes it harder for marine animals to make shells since they can't get the calcium they need out of the water.

[@khuongpham5516]

Very rewarding to watch this after my thermodynamics unit in Gen Chem

[@Matheuzers]

we cooking

[@mrhassell]

Ideally with gas

[@einszwei6847]

I was a little bit confused about the argument at 35:35 because she said "Omega is equal to one" because the atom is in its one ground state. But aren't we interested in Omega as a function of U because we want to take del S/del U? If yes, we don't want to just look at the ground state, we want to look at excited states and how their number changes with U. Here is how I think this would look: If the particle is free, then U would just be its kinetic energy p^2/2m, i.e. proportional to p, so if we assume that there ist some "constant density of states in p-space" (something like (2 pi)^dimension/V) the number of states with fixed energ U should be approximately proportional to the area of the surface in p-space with that energy, which is a sphere when U=p^2/2m. The area of the sphere is pi p^2, which is proportional to U. So Omega is some constant times U. With this S=k_B ln(const. times U) and del S/del U=k_B/U. This means temperature for one particle would indeed be well defined in this case as T=U/k_B.