The First Law of Thermodynamics: Internal Energy, Heat, and Work

[@myron_jd1272]

Sometimes hearing the same information from a different person helps very much!

[@sadhanajoseph2320]

I agree with you.

[@سارة-ط6ق1ي]

يا رجُل ماهذا الشرح الجمييييل ، شرح مُبسط وجميل ♥️♥️♥️♥️👏🏻👏🏻👏🏻

[@abdulrhman.3742]

كملتي معه ولا ؟ عندي اختبار بكره.

[@Rahul-hp5ie]

I swear to study thermodynamics eagerly if he's my professor.Deserves a lot of subscribers and likes.

[@heliumteam151]

Me watching this 5 min shit after studying this for 13 hours straight in a complex way and dreaming about this video to be enough for my exam ....

[@Maxz-lg1et]

For those who are confuse, there's two perspective here System (mostly use in chemistry) and the Surrounding (mostly use in physics), W = Q + W (chemistry) (system's perspective) >When W is negative (-W) work is done by system, >When W is positive (+W) work is done on the system W = Q - W (physics) When W is negative (-W), work is done by the system When W is positive (+W), work is done on the system

[@Zempie]

you just wrote the same convention pair twice.

[@loreenzo2120]

@@Zempie not rly cuz the equation is different

[@Zempie]

@@loreenzo2120 I meant the description of the equation. it should be opposite for one of the scenarios

[@loreenzo2120]

@@Zempie huh, yeah, the signs should be flipped for the last one

[@cherylbauman9510]

Why couldn’t you have been my professor in college? You explain everything perfectly!

[@thanos5466]

U should do study My girl 😂😂

[@fishplayztoh]

Yes

[@jefrreyjeffery2192]

You study this in college. We study this is in 10th grade in asia💀☠️☠️

[@anuragchaudhary6307]

@@jefrreyjeffery2192 We study this in college too, we do more than this, but I'm coming back to the basics, Also Asian here.

[@Evangeline_Hansen]

​@@anuragchaudhary6307maybe you two live in two different countries/regions ,after all Asia is a big place

[@maelscott7212]

Great video, one thing you missed that I think is important is if U = q - w or = q + w depending on which subject you're taking. I know that physicists and biomedical engineers use +w.

[@shreya_0412]

This is my confusion too... When to use which one?

[@wetworksyt4446]

​@@shreya_0412if work is being done on the system, w will be will be positive and the equation will be U=q+w. If work is being done by the system, w will be negative and the equation will be U=q-w.

[@aurickbiswas8233]

​@@shreya_0412 in chemistry work done by the system is negative and in physics work don by system is positive. Think of it like physics is oriented with profit and loss while chemistry is more about caring about the system like a baby😅

[@Sulfuricacid__140]

i want all Teachers as you. You explain a lot of things in few minutes.Thank you..

[@TomBrooklyn]

As always, clear, and most importantly, concise. No wasted words or time. Well done, Professor Dave

[@nischalchhetri7445]

I don't know if I have gotten this all wrong, but isn't the sign convention explained here wrong? 1) Work done by the system- (-w) 2) Work done on the system (+w) This is what I have learned. Please correct me if I'm wrong. Edit- So this tutorial was for physics, not chemistry. Anyways, it's more interesting to discover that we use different sign conventions in physics.

[@markvillacampa4314]

I am looking for a validation of my understanding of the work done on the system because I feel like what is in the video is wrong, and I found this comment hahahaha. I searched for the work done on the system in physics and, similarly in chemistry, they are positive. So the video is indeed wrong.

[@AR14SigmaGulfam]

Yes, video is telling wrong about the sign conventions.

[@abhi22]

@@markvillacampa4314 The video isn't wrong. He has changed the signs in the equations too. So the equations will always work. It's just a different perspective to look at.

[@borapadmanabham3676]

Yes work done on the system is positive, work done by the system is negative

[@legendaryx2k19]

Well the sign convention don't matter much as long as they are opposite in any case

[@vaishnavipatil2972]

Best video for understanding the concept

[@MattMattMat]

Professor Dave is definitely still saving educational lives years later with these videos

[@WritersDigest-b8f]

Exhaust stroke & also intake stroke are adiabatic processes because no heat is added or removed in the processes and internal energy reduces in exhaust stroke and internal energy is added in the suction stroke. Accordingly work is done by the system reducing the internal energy in the exhaust process and accordingly work is done on the system to shoot up the internal energy in the suction process.

[@USArmyVeteranOIFandOEF]

Awesome visual examples and simplified to absorb the information being released, making understanding and keeping it in so much easier. Thank you, Prof. Dave!

[@tommysheehan2136]

Professor Dave helping me cram for the physics GRE, what a hero

[@derrickdanso6631]

You're making me fall for thermodynamics. Thank you so much

[@VishnooSpotlights]

We need more professors like you in India ...

[@skullmax3595]

Exactly

[@Vagdebrume]

You do an amazing job ♥ !

[@Luke-t4f3x]

3:29 dude you're wrong bro... If work is done on the system, its sign is positive. If work is done by the system, its sign is negative.

[@Kyrmen-b4h]

Right 👍

[@prishaendait8621]

its because the sign convention used here is valid for physics but not chemistry and I think he made it from physics point of view.

[@minimidder2025]

Why does this channel have so few subscribers???!! You're amaze man! Thanks! ❤

[@khaledzainel-dein3766]

Thanks for your brilliant explanation

[@v2sisters138]

Amazing video! But please specify that this is from physics' point of view. according to chemistry the signs are different. This kind of induces confusion. THANK YOU!

[@sychomadman]

thank you so much. i thought i was going crazy.

[@na-chan163]

@Mohamed Sherif how is that so?

[@fatimaisra9143]

@@na-chan163 the surrounding energy is the atmosphere's energy and the system's energy is the internal energy

[@na-chan163]

Fatima Isra work done by system (expansion) is negative for chemistry but positive for physics. Can you pls explain this?

[@fatimaisra9143]

@@na-chan163 it's positive in phyics because we are describing the system's actions on it's surroundings, and it's negative in chemistry because the system is "throwing" out work (idk if im completely correct but im sure this is a good way to think of it)

[@EngineeringStudyMaterials]

Thank you for making this video. Well Explained. It Helps me a lot.

[@ziadyasser8888]

man... u r the best one explain this .........so thank u

[@N3thStudios]

Thankyou Professor

[@Unknown_Ooh]

I think I'm dropping thermodynamics

[@Traewing]

😂😂😂😂😂

[@cephasdn6576]

😂😂😂😂😂

[@bhumikaulangwar9056]

Good one 😂

[@LawsonHanson200]

😂😂😂😂

[@NoriousKumwenda]

😩😩😅😅😅😅

[@benYaakov]

IUPAC said that work done by the system is negative and vice versa

[@baurzhanhydros9957]

expansion of the gas W < 0 and compression of the gas W > 0. Because in the first case, the system does work on the surroundings so it loses work while in the second case, the surroundings does work on the system so the latter gains works which will be positive

[@BOLYANA]

3:49 isn’t if the work done by the system then it is negative?

[@MohanySoliman]

Good

[@tkub77]

Great video! This helped me a lot!

[@TheMultipower47]

I wish your channel was bigger

[@ProfessorDaveExplains]

me too, friend!

[@Lioooooooo1ooo7oooo]

It is now

[@unknown-gy8jz]

Now it's bigger than ever!!!

[@eyerus-uw7gt]

@@ProfessorDaveExplains that's amazing and could you explain why U become zero when temeperature is constant plz ?

[@HarshaAbey]

thank you

[@prishaendait8621]

Everyone wathing this video please do note that the sign convention used here is only valid for physics, it is the opposite for chemistry.

[@makeitmemorable__]

Sir you have done wrong here about sign convention work done by the system is negative and work done on the system is positive

[@ProfessorDaveExplains]

That's chemistry. This is a physics tutorial.

[@makeitmemorable__]

@@ProfessorDaveExplains okh sir my mistake actually I am in 11th class and a neet aspirant so I don't know it well and thankyou for replying

[@Mohith1111]

​@@makeitmemorable__ lol same

[@hja9157]

Love to hear more from you

[@captainldd]

I loved this video. so much good information!

[@Ali-cc3zz]

بارك الله فيك... God bless you

[@muftiaaishasuhail3050]

Thanks a lot sir! You made it easy

[@muhamadabubakar7621]

Sir your way of explaining topic in detail is the #best.....

[@LarryWater]

Thank you so much!

[@ahmedelshazly4139]

awesome, great job professor . keep on

[@ViaDenglas-xz4th]

THANK YOU PROF!!!!!!!!!!!!!!!!

[@crescencelee5112]

short and easy to understand thanks

[@bjalle3569]

Nice video Dave, really helped me and my buddy Johan learn thermodynamics :)

[@kripashankarshukla4073]

You deserve to be a noble prize winner. Sir you are awesome you should get a noble prize!!!!!

[@abdurrakib551]

very good expression sir!

[@niceguy4801]

Thakyou professor dave!

[@sadhanajoseph2320]

thank you sir.

[@jacobthonkuotamol4927]

I don't think there is someone like Professor Dave on the planet Earth. I am just waiting for your inventions or discoveries my Professor.

[@WritersDigest-b8f]

Professor Dave: could u do YT thermodynamics videos with examples of processes from IC engine, jet engines, rockets, compressors, gas turbines, steam turbines, boilers, refrigeration cycle, heat pumps. Thermodynamics concepts would stick to comprehension and memory by using heat engines as examples. This video was fantastic and not easy to forget now because u used mechanical examples. Thank u so much

[@B-MAN95]

I'm really impressed , the way of teaching, how u remember all those things, can u give me any tips to remember easily

[@rachellicari5964]

***My chemistry teacher has told me +w=work done on system, -w=work done by system

[@carultch]

Different disciplines will prefer different sign conventions. I'm accustomed to the heat engine sign convention, where work done by the system is positive.

[@manishkanna532]

superb nd simple xplanation

[@sajukgeorge3399]

thankyou sir, it is very useful for me

[@ashensaranguhewa]

Thank you!

[@johnrayrivas1375]

Great explanation... Thanks

[@leunam1leunam172]

Very great video

[@dimitrideville7514]

Thanks a lot!

[@ramb0077]

thank you very much and wish you good future

[@mahiyarahman5099]

Thanks a lot🌼 Amazing!

[@siddhantgupta3500]

Thanks dave

[@jerichoytprem4527]

Wow. Thank You

[@physics20246]

Exordinary, congratulations, Sir

[@miniaturenature2507]

Amazing sir 👌 Wish you have more successful in life

[@ayesha4599]

Professor Dave is amazing, honestly!

[@mohanraj-rw9du]

Good explanation

[@333_studios]

Why does my textbook say deltaU= Q + W ?

[@mufakkirhussain2816]

333 Studios cuz you are Indian. You consider work done by the system +.

[@TheMWBooher]

Engineers and Chemists view work differently. As he explains, Work is positive if the contained volume does Work against the atmosphere, like the expansion of a gas in a piston assembly. Chemists view Work as positive if the environment does work on the contained volume, such as a compression of the gas.

[@Amityadav99.]

Mufakkir Hussain it is in physics but in chemistry this sign is reverse of W

[@v2sisters138]

Wrong, because he is studying chemistry, and you are studying physics.

[@ranjeetsohanpal752]

Even my textbook is saying work done on the system positive

[@RANJANKUMAR-oj4wm]

Nice work

[@icelerez]

This is a great video! i just wish you wouldn't have used capital letters when referring to heat and work because they aren't state functions and should be lower case. Anyways thank you for helping a whole generation of students through college.

[@nokitosembrano3657]

how about isobaric

[@eshaan2500]

Mr. Dave, you are awesome

[@karthikswaminarayan4278]

please make a video on carnot engine or carnot cycle

[@ProfessorDaveExplains]

that would be the second law, the one right after this!

[@karishmakaushik9491]

Thankyou!

[@ayushijain8671]

Excellent for revision, short and crisp, covers all points quite well. Thanks a bunch. I also love your organic chemistry and dna-rna videos.

[@manoharapproach7178]

Thanks for the video, but am confusing a bit . If work done by the system that mean system loss energy to surroundings which decreases the internal energy of the system , so it should be negative. Please need more explanation

[@evelyntromp789]

I’m obviously not Prof Dave but I think it’s positive because the equation has a negative W, whereas most equations have a positive work (dU = Q + W)

[@ilhamnaim9541]

i love your content. pliss don't die❤❤❤

[@AyatMohammed-y1h]

thank you now i understanding therom esay.

[@mostafaelsheikh604]

thanks much❤❤🌹

[@shadowx5443]

Thks sr you're legend 😎⚡

[@amlansasmal]

you are awesome sir i was unable to understand this topic...again again.... but your way is very simple and very useful to me.... keep on sir...that has a positive effect on us...😀

[@EnricoMicheli-jo6bg]

Anyone else got exam today GL Guys also Professor Dave u a life savour

[@aneeshaperera6680]

Thanks sir.we are hoping to a vedio on minerals .

[@Ice-yp4wg]

Question: Why must heat be represented by "Q" and internal energy is to be represented by "Delta U"?

[@poorleatherwallet]

delta U means the overall change in internal energy. delta U= U2 - U1

[@Ice-yp4wg]

@@poorleatherwallet but why use U specifically?

[@poorleatherwallet]

@@Ice-yp4wg wdym? Specific internal energy? Sometimes questions want u to find out the internal energy of the system before it went under compression or expansion process

[@Ice-yp4wg]

@@poorleatherwallet The letter U I mean

[@poorleatherwallet]

@@Ice-yp4wg no idea. But I guess it's because it's a good letter to use since other letters are used to define other properties such as temperature, pressure or enthalpy

[@devi.official23]

Tq very useful

[@shahxad6533]

why was (150J) taken positive ??? In the Last Example.?

[@fexofenadinaGenerica]

Awesome tutorial.

[@ZemedTekle]

Please done the material balance calculation of chemical engineering

[@guledchemist8264]

good explanation sir

[@nourhannenagy7666]

When work is done by the system W is negative when work is done on the system w is positive

[@nourhannenagy7666]

You said the opposite

[@ProfessorDaveExplains]

Chemistry and physics have opposite conventions. This is a physics tutorial.

[@Endless20162]

@@ProfessorDaveExplains ahh so that's why

[@parpeez]

This is a really clear video buddy!

[@devnaathpillai]

Isnt work negative when it is performed by the system or am i trippin?

[@devnaathpillai]

@ProfessorDaveExplains

[@runbou3485]

Thanks you អរគុណអ្នក

[@小C-w8h]

so helpful

[@baslielalene4702]

Thanks.

[@Juboury_20]

I think there are mistake in work subject

[@muhamadabubakar7621]

Amazing sir

[@INAYATULLAHSHEIKH]

Outstanding

[@ARJUN_Tamulpur]

Thanks sir

[@haithamalhakemi6239]

THAT WAS REALLY HELPFUL. THANK YOU SO MUCH