Kinetic Theory and Phase Changes: Crash Course Physics #21

[@crashcourse]

We made quiz questions to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/3TW06aP

[@bio_5467]

These kinds of channels are much more interesting than school

[@ishanr8697]

They only have to hold your attention for ~10 minutes. Try binging on these for around 6 hours a day, 5 days a week for a decade or so.

[@PeacefulAnxiety]

Great episode! It is a shame that viewership is so low for Physics.

[@ishanr8697]

I feel that way about biology.

[@markholm7050]

+Ishan R Man, when I took that college botany course I could not imagine how anybody memorized all that stuff. Intro physics was a breeze compared to that.

[@bolerie]

I like how everyone demanded CC Physics, but now that it's here, it gets the fewest viewers of all the series that are running at the moment :/

[@D__x]

It is not fun, not interesting, and useless. Way to much fragmented even for index.

[@theplainblonde]

It's because the subjects discussed so far have been incredibly boring. The entire series consist of 11th grade physics. People are just interested in more advanced subjects not cursory definitions of derivatives and basic kinematics.

[@liawxinyan]

Actually, everything taught here is basics, which is what i'm learning now so it's extremely helpful because they post at the same time my teacher teaches the same topics.

[@Rhaegar19]

+iTuneTime That's because it's a crash course. There are other channels like PBS spacetime that do more advanced stuff.

[@SheikhEddy]

This is actually the series I'm most interested in.

[@Victoria-yp3eb]

I absolutely agree, a math series with the ease and casualness of Crash Course, would be monumentally beneficial for a lot of students across the world. Starting at Algebra 1 and Geometry (for an intermediate Mathematics Series) Algebra 2- Trigonometry- Calculus AB - Calculus BC- Statistics ( for an advanced Mathematics Series)

[@anotherdoseyt]

hey do you think you could you can start an advanced maths series

[@crashcourse]

We are always brainstorming it and trying to figure out what would work best. It's not off the table, but we're definitely taking our time with it to make sure we do a good job. - Nick J.

[@prestonpls1001]

+CrashCourse I hope it's something in the difficulty level at or above Calculus.

[@theflaggeddragon9472]

Tensors?? :D

[@PeacefulAnxiety]

It is more that people aren't doing what they should be doing when it comes to learning physics and people are being. The thing is that she is explaining equations with numbers and rules and that takes a bit to fully sink in leading people to people's brain so by the next time she starts explaining the next equation people haven't figured out the last one and so it stacks making it harder to swallow the video in one big gulp. The other problem is that people aren't doing practice problems on their own and just watching CC leading to them having a worse foundation making it harder from them to understand the next lesson so it all snowballs into confusion and frustration making people drop it.

[@markholm7050]

+KappaW A lot of this series is at the level commonly taught in a decent high school physics class. Some is from 1st year college physics. The pressure, temperature behavior of gases usually gets a bit more coverage in high school and 1st year college chemistry.

[@NaquadahEOD]

Kinetic Theory and the Phase Changes would be a pretty awesome band name.

[@AdrianaDonado]

Thank you so much for these videos. I'm actually seeing heat and waves at college right now, and this is very helpful

[@DocSchuster]

At 4:50, Shini claims that at higher pressures, real gases tend to have a bit less volume than ideal gases. This is incorrect. The compression violates the assumption that the molecules have no inherent volume, so the real gases have MORE volume than the ideal prediction. She's right about the too cold situation. It's interesting that the direction of the deviation from the ideal depends on whether it's too tight or too cold!

[@wishdoom]

Triple point just blew my mind!

[@romanfox5368]

Wow. That was really cool to see a graph explaining dry ice.

[@cosmicfool6830]

One thing that struck me earlier, though it is more a chemistry thought. Does a single atom have a state? Can it be a liquid, a gas, or a solid, without other atoms of its kind to interact with?

[@Muskaan._.taneja]

No..state is only a bulk property

[@Joel-oe7ud]

Nope state of the substance depends on the force of attraction between it's constituent particles.If we consider a single atom there is no force of attraction to consider and therefore we cannot define it's state.

[@CHAS1422]

Excellent series...totally coherent and lucid. Thanks for posting.

[@jasonpatterson9821]

6:28 Critical pressure is NOT the pressure at which a substance remains a liquid regardless of temperature. There is no such pressure, as we can always exceed the critical temperature and create either a gas or supercritical fluid. Critical pressure is the pressure at which a substance remains liquid at the critical temperature. The (x,y) coordinates of the critical point are (critical temperature, critical pressure.)

[@varana]

In general, this is great... but please, slow down a bit. :) Especially when reading formulae. Also, please back up calculations like the one starting at 3:10 with a visual aid. I get the 300 K, but even though I'm quite proficient in English (which is not my native language), I completely black out at the number that follows, which means that while I still try to process this number, I'm not focused on the equations that follow, so I miss a good deal of those as well, and so on. It's on screen later on (from 3:36) - for about two seconds, so I almost certainly have to rewind because I missed the opportunity to pause the video while it's there. Even though I liked the math-y parts of physics, and have no problems understanding the calculations in principle, and know English well enough to understand these videos, the rapid-fire delivery makes it unnecessary hard to watch them. But generally: please keep doing them. :)

[@bernietoyranes1057]

varana312 agree

[@vie_lit]

YES! She was going soooooooo fast and on top of that the timing for the visuals weren't that great. I think I'm just gonna check out Khan Academy

[@fay7725]

Well they made it that way intentionally. The purpose is to catch the viewers attention and prevents them from getting bored. It'll feel more engaging and active for the viewers that way. The pause button and the subtitles exist for a reason. You can pause to process everything, and go back and forth if you miss anything. I watch Khan Academy a lot, too. But sometimes it is way too slow and I felt less engaged. For the sake of general understanding, Crash Course is a great place to start for me. For a more in depth calculations and details, Khan Academy is the way.

[@Vividlyvanilla]

I love the speed of it

[@arathisuraj856]

This series is great for a quick revision or basic intro to Physics 1 and 2. Pity it doesn't have more viewers...

[@randy109]

Even though I have 3 College Degrees that I earned 40+ years ago they were not in the Sciences. My son has advanced degrees in Engineering/Physics/Electrical Engineering. My daughter is a Math Teacher in a rural Elementary School. I never even took Physics at all. Over 90% of American adults have never taken any advanced Mathematics OR Basic Physics. Even when explained at an elementary level most Americans don't have the Mathematics background to understand even this video. I wish I had taken hard sciences and mathematics in my "College Days". That is why this video has so few viewers, sadly...

[@ladyagony2018]

Dr. Shini is so cool

[@borismatesin]

Please feed your proof-reading team stronger coffee, they keep spelling "kinetic" as "kenetic" :D

[@crashcourse]

Ah, poop. Where?

[@crashcourse]

Nevermind. I see it. SHOOT!

[@colleenz.2477]

hahaha. more caffeine!

[@benaaronmusic]

+

[@enkiimuto1041]

That was neat, I always wondered how did they measure altitude on other worlds.

[@vnana2001]

This was a super cool episode

[@noranel-sherif1263]

Another Thankyou.. Loved the Beginning and Ending Story - chapeau to the application "choice" of the theory

[@hunterkubat4805]

a lot to grasp, but a god send- thank you

[@MusiCaninesTheMusicalDogs]

Cool! The triple point of equilibrium explains a lot about what we see around us here in Earth! 👍

[@jenjacobs4197]

I know this is dorky...but i love awtching these videos just for entertainment! But i like it when John Green does the teaching for History! But overall, this channel is....DA BOMB!

[@anastatianeromanijournalis8894]

Thank you for your time and consideration in this matter

[@Stillwon8]

My teacher used some of these videos for my class

[@TheJaseku]

Wow that was excellent !

[@peachesnpearls5506]

i love learning physics😘😘😘😘💜💜💜

[@javeriafaisal1525]

1:49 when speaking kinetic kenetic makes you write it kenetic. Great episode btw.

[@markholm7050]

Commenters on this series have frequently complained that the material is too advanced. This is disappointing to me since the level of the material is the same as standard high school physics with a bit of calculus added, and since the series got into gases, a bit of high school chemistry. I wonder if another attempt might be made, introducing physics through the common laboratory experiments used in high school and college classes? The first experiment in my high school physics class studied the acceleration of a falling weight using distance vs time. It is pretty real when you measure the distance intervals on a paper tape using a meter stick, and plot them to find a nearly perfect parabola.

[@grndragon7777777]

thank you

[@rkpetry]

Critical Temperature [06:03] and Critical Pressure [06:29] sound in conflict-as if at higher temperatures-and-pressures it'll never condense and, never boil, but remains, whichever it is, or was,-sort of a biphase blobular 'gasliquid'...? (We can suppose it'll creep-adjust....)

[@pairot01]

7:55 Hold the phone! How can the triple point be _defined_ at 273,16 K when the Kelvin scale is already defined otherwise?

[@sudeepjoseph69]

Maybe it has coronavirus?

[@mdnisumon7332]

You are so creative I always follow your video. Go on sister

[@MECKENICALROBOT]

oooooooh, so in Dragon Ball, when a character is charging up, and you see the energy they give off, *THEY'RE JUST SUBLIMATING!!!!*

[@Kris-jx8ih]

Lolz

[@ZodieRoadie]

Can you please do a law series

[@AdrianInniss]

this is amazing!

[@bullsontherun9340]

I love your videos and have been watching with my niece and I am helping with homework but I can not finish this question. Any help would be great.Thanks in advance,Oxygen has six electrons in its valence shell, while magnesium has two. Both can reach stability when magnesium donates two electrons to oxygen. This results in oxygen becoming an anion, and magnesium becoming a cation, which then stick together. Is this an example of an ionic or covalent bond?

[@siaw0000]

Dude that's chemistry

[@javeriafaisal1525]

But it's an ionic bond because oxygen will acquire negative and mg will acquire positive charges. There is no mutual sharing so it can't be a covalent bond.

[@anishtiwari1121]

Our school should show CRASH COURSE videos and the syllabus will be over within a month.

[@americanenglishazerbaijan]

She is amazing

[@LuisCurrupaki]

Well I know the chances of you answering me are incredibly low, but I do have a question and I hope for the slight chance to occur: During the mission planning, was it considered the actual atmospheric pressure measured or was it relevant to evaluate the hypotetical atmospheric composition of a determinated previous condition on the planet to set the reference point as the triple point? Because, if I'm not mistaken, there would be an increase on the pressure gardient with a thicker atmosphere causing a decrease on the altitude of the reference point, leading to a deviation on the data analysis on further stages of research if you were to compare to anything we can measure or quantify here on earth. Meaning you'd need to look for something "deeper" than you'd think it should be, am I wrong?

[@sterlingbear6988]

perfection

[@sharesh868]

Great episode. It is a shame that viewership is so low for physics super sister

[@AnlaufGleitgel]

somebody else who sucks at physics? :P

[@jackcarter4844]

here haha

[@hannah6492]

lol

[@jakeroosenbloom]

I consider this more as Chemistry, but yeah.

[@AnlaufGleitgel]

+jake roosenbloom yeah thats how much i suck haha

[@markholm7050]

+Jake Roosenbloom There is a discipline known as Physical Chemistry, also a standard course in the Chemistry bachelors degree program. This material fits right into the first couple chapters of that course.

[@anthonymarcyes3054]

Love you!

[@sassysudz1]

Triple point = mind blown

[@xMack_]

Are any of Sci-Show or CC videos demonitized now?

[@Doc_Loc]

PHASE CHANGES YESSSSSSSSSSSSS

[@readytowearpyjamas]

The body of theory which explains the physical properties of matter in terms of the motions of its constituent particles

[@priyanshpathak26]

how you make these animation?? where I can learn to make these kind of animations??????

[@shreyodebnath2813]

Hire thought cafe.

[@paurushgargtube]

Awesome

[@majesticpug6982]

I've watched very single crash course video for fun and i am in grade 4 standard 2 and i'm the smartest in my school I've moved up 2 grades!!!!! watch these people!!!!

[@yessenbayev]

Kenetic energy... Yeee

[@chtahnamte]

i think i'm in love

[@rn5538]

This is really great. I assume. I'm way too stupid to keep up

[@horizon241]

Is that Millennium Falcon the very same one that Hank built with Michael Aranda?

[@saikat5488]

There is some mistake I assume, the liquid could be boiled above the critical pressure.

[@17thcolossus91]

Thumbnails always doing people dirty

[@natalielin8138]

Can someone correct the spelling of "kinetic" at 1:50 :(

[@michealmclaughlin429]

Awesome, loved the graph. Visualization really helps with understanding

[@futureDK1]

Do crash course sociology!

[@noealva]

hell no

[@gregmiller9710]

that;s not very social Noe..

[@noealva]

Greg Miller just dint like it lol

[@sexybeast7728]

why the hell not? PS. is sociolgy same as social psychology?

[@futureDK1]

+Sexy Beast I'm not honestly sure. Probably not, because of the difference in micro and macro on populations, not sure. Have to do research on that.

[@VR_Wizard]

I was so curious what happens if you step over the critical point by rising the pressure and the temperature a little bit more. I found out that you reach the realm of super critical fluids which behaves like liquid and gas at the same time.

[@DustinRodriguez1_0]

How many entities (molecules, particles, whatever) are required for phase changes to be a thing? I am asking in the most generic sense possible, not in the specific case of the 'phases of matter' being described in this video (which, BTW, why did Bose-Einstein condensates and plasmas not even get a mention?). Phase change seems to be one of the only general concepts which can apply across all complex systems, but it seems to not be terribly rigorously defined. Obviously you can't have it with 1 entity, as it is an emergent property of interactions, but can you have it with 2? Can 2 molecules of water be a 'solid'? Or do you need more? How many? And why?

[@akhilpeddikuppa5331]

1:55 isn’t it spelled kinetic

[@rioshark8022]

2:04 kenetic energy

[@lanzhang3959]

it seems Dr.Shini has tons of check tops

[@leytonjay]

You are brilliant and as you're British I believe you just a little tiny bit more than the American Brothers, dunno why.

[@calculon000]

Is the metallic Hydrogen that is theorized to be at the core of Jupiter just Hydrogen that exists at pressures high enough to be on the solid part of the phase diagram?

[@calholli]

0bvi0usly

[@markholm7050]

Yes and no. The pressure is so high that the hydrogen starts behaving like a new material, electrically conductive, solid hydrogen. The theoretically required pressure is so high that the existence of this form of hydrogen is still unconfirmed. Also, liquid metallic hydrogen is a theoretical possibility. The pressures involved are much higher than Dr Somara is discussing.

[@uchennamaduno5799]

1:48 I read that as genetic energy.

[@nobodyhere703]

Can somebody please explain why water that has a higher temperature than the critical temperature can not become a liquid regardless of how high the pressure is (6:00), but at the same time it can't become a gas if it has a higher pressure than the critical pressure? How does the water behave if both critical points have been exceeded?

[@Rhaegar19]

It's a liquid-gas...thing called a supercritical phase. The molecules are too energetic to settle into a liquid, but packed too tightly to spread out like a gas.

[@nobodyhere703]

+Rhaegar19 thank you

[@dianagonzalez8625]

You should make geology videos

[@thebloxxer22]

Can't seem to find anything about Plasma here or later on.

[@art-is-awen8842]

Please do a Sociology and an Art History crash course!!!!

[@MrLeeKnees]

Yes... I know some of those words.

[@AdrianaDonado]

Can I help with the subtitles in spanish?

[@ezekiel0606]

+

[@AdrianaDonado]

+Deborah Meltrozo por qué?

[@kinghasturFFFF00]

¡Hola! Si, claro. En la parte de abajo, a un lado de compartir, esta el apartado de "more" o "más", y ahi puedes darle click a transcripción. Luego, en la parte que dice inglés, tienes que darle click, y te dará la opción de agregar subtítulos n.n Gracias por ayudar a contribuir al conocimiento )o)

[@carloscerritoslira328]

Por supuesto

[@ZeeGhost713]

Hola if you don't know that means hi 😂

[@torestgard1681]

How did they actually find the correct altitudes on mars? Yes, the pressure was above 6,1 mBar. But how did they find where this was/is?

[@Rhaegar19]

My guess would be: find the composition of the atmosphere by looking at how it scatters light, then use what we know about our atmosphere and gases to predict how the pressure varies with height. Since then I'm sure they've made this more accurate with actual measurements from the probes, etc.

[@assalane]

direct measurements I'd guess. Or maybe by using the mass of the planet and the height of the atmosphere to derive it. Or most likely both.

[@markholm7050]

Both infrared light and microwaves are absorbed by various atmospheric gases. We had an approximate idea of Mars atmospheric density before spacecraft ever went there, using Earth based telescopes. The spacecraft enabled better measurements by putting a calibrated microwave transmitter in orbit around the planet, so that it could be observed from Earth. Mariner 9 included both infrared and ultraviolet spectrometers. Both of these instruments can contribute to atmospheric measurements. Given that Mars atmosphere is largely carbon dioxide, the infrared spectrometer should have been particularly useful.

[@mdmubtaseemahnafaronno5533]

What's kenetic?

[@Romanreigns-xt8gn]

nice

[@saulcoria8679]

watching this before I take my chemistry exam...

[@tsukuyomi4650]

How does the kinetic theory explain how: a piece of ice changes into water?

[@princesswonderwoman6209]

This made me want to drink water......

[@AmberMaryAnne]

If only u were my physics teacher

[@shojintam4206]

Kinetic theory of gases Root mean square speed Phase changes Critical point Triple point

[@IoEstasCedonta]

...wait, where the heck does that math come from?

[@kickinbirdt250]

For the most part, the mathematics behind these equations are well beyond the scope of this series. For that you'd have to spend a year or two in university studying this stuff before you can start making sense of the their mathematical proofs.. They involve pretty heavy calculus and differential equations from what I understand.

[@bmzaron713]

This video was very cool.. I think the strangest part was that the interactions of a gas at varying pressure or temperature was considered 'strange'.. It makes sense when you think of the gas's polarity and subsequent interactions with other atoms

[@darko.v]

please someone explain this to me: Imagine a situation where we dig up a tunnel far below a mountain. We put pistons that contain any fluid that could heat up. We submerge them in a pool of water and ha a system similar to a power plant (water vapor to move giant turbines that produce electricity). We then put enough weight on top of the pistons so they heat up, water evaporates and we get electricity. Would this work and would it be worth it?

[@livinsite1]

How will the heat be conducted to the surface and be converted to keinetic energy .... When the heat is conducting by any chance .... The pressure will drop as the heat drops due its conversion to keinetic energy in a turbine for electricity as you mentioned .... So it's not possible .... In simple words ... When energy is converted from weight in form of Keinetic energy to heat energy so much is lost in friction and other sources .... Why not just use all the weight in first place to try and turn a turbine .... See you just now know that will not work ... That's how your idea will also not work :P hehehe

[@Sarcasmitron]

The process of putting weight on and taking weight off the piston would use more energy than it would produce.

[@darko.v]

+Sarcasmitron My idea was that it's a one time thing of putting weight and the constant pressure and giant weight produces enough heat to boil the water and keep it heated for some time.

[@Ddub1083]

Would this work? no.... would it be worth it? see answer 1.

[@markholm7050]

You have not described your hypothetical system well enough for any detailed analysis. If you are describing a system in which you put in work of one kind and get out work of another kind, then the answer is a qualified yes. You can transform one kind of work into another. The catch is that there are both theoretical and practical limitations. The theoretical limitation says that you can never get out as much work as you put in. In fact, you usually lose a lot of your input work. The practical limitations say you will always do worse even than theory allows. The very best coal fired, steam power plants are below 50% overall efficiency. Natural gas cogeneration plants can get into the high 50s. That is about as well as you can do with a thermal power plant. It is not for lack of knowledge or effort, the natural world makes those limits.

[@Qermaq]

I wish I could see what's on her tshirt.

[@54321conor]

At 2:06 you spelt kinetic wrong

[@kastochan]

hey recognise her from al jazeera :)

[@radagastwiz]

So, Hank, what's the news from Mars this week?

[@ninjatakes4321]

I really, really like your shirt. I want it. Can I rob you?

[@gregmiller9710]

..i like her pants..i'm gonna talk her out of'em XD

[@milansenthilkumar9711]

Dumbo talk,like that to me in real life I will beat you up

[@keghnfeem4154]

I could never find a extensive resource of phase diagrams for atoms or simple molecules.

[@markholm7050]

Phase Diagrams of the Elements, David A. Young, September 11, 1975 www.iaea.org/inis/collection/NCLCollectionStore/_Public/07/255/7255152.pdf

[@keghnfeem4154]

Thanks

[@cxang]

Does anyone feel that this arrangement is rather echoy?

[@KRISHNA-uy3ns]

I think I have saw u on al jazeera

[@YoshithWeerakoone]

KINETIC not KENETIC - right?

[@incognitox9551]

Last time I was this early... Ok, I'm gonna shut up

[@bowiebrewster6266]

so what happens is water is hotter than 647 kelvin and under more than 22Mpascal ?

[@Rhaegar19]

It becomes "supercritical". Basically the words "liquid" and "gas" lose their meaning and you're left with this weird soupy mist. There are lots of videos of supercritical CO2 on youtube.

[@calholli]

basically it bec0mes a mix 0f b0th liquid and gas... if y0u were t0 l00k at each m0lecule 0ne at a time... they w0uld be in different phases at different times depending 0n the exact l0cal c0nditi0ns f0r a given time... but change w0uld be king

[@markholm7050]

+calholli I think "mixture of liquid and gas" is misleading. In the supercritical region, the density and properties that depend on density can, if you are in the right part of the diagram, be near those of the liquid phase, but the viscosity and diffusivity are more like the gas phase. It's not all one thing, either, as the properties vary continuously all over the supercritical range. You can be more liquid like or more gas like or in between. The one thing you can not have, in a simple system, is any mixture of liquid and gas.

[@vc5212]

Ok

[@SaulSalt]

dont like like the high echo. some foam could help

[@notknot12knots]

On an off topic... Crash Course Linguistics?... or Geography?... please...