Thermodynamics: What do HEAT and WORK really mean? | Basics of Thermodynamics

"Work" and "heat" are commonly used words in everyday life. But they mean very specific things in the physics field of thermodynamics.

Hey everyone, in this (rather short) video I wanted to discuss the exact definitions of the words "work" and "heat" in a thermodynamic context. These words are very easy to get confused, especially because their definitions have subtleties to them that are difficult to teach and understand.

And then there's the added complexity that these two words are used in day-to-day language to mean very different things to what they mean thermodynamically. So it's important to really nail the definitions right at the outset, before delving more into the world of thermodynamics.

Work in thermodynamics is a specialisation of the physics definition of "work". This is often defined as a force x a distance moved by the force, but in thermodynamics it refers to the energy transferred to / from the system, in a way that involves the presence of detectable macroscopic (large scale) forces. Other energy transfers certainly involve microscopic (small scale) forces, but for an energy transfer to be defined as work, large scale forces must exist.

Heat is the other kind of energy transfer - one where NO large scale forces are involved (assuming we're dealing with a closed system). In other words, assuming our system is not exposed to the external environment, any energy transfer that is not work, must be heat by definition.

If you enjoyed this video please do hit the thumbs up button, and subscribe for more physics content! Head over to my second channel, "Parth G's Shenanigans" if you want to hear some music, and follow me on Instagram @parthvlogs - thanks for watching :D

[TomTom-rhgk]

You admit the truth. None of us understand thermodynamics completely. I have learned lot from your video.

[andragavril]

Im having my midterm tomorrow and one of the chapters i have to cover is thermodynamics and Maxwell s ecuations so thank you for your videos. They really help!

[tejasdeepsingh]

I am a simple man. I see Parth, I click.

[nunushetmitiku]

Thank you for your hard work during this time. this is the channel what I have been looking for 😍😉

[MetadelHaymanot]

I admire you very much since your teaching method is so clear

[radhikashenoy]

Parth: simplified version of heat and thermodynamics.
Me: hit subscribe button press bell icon and give thumbs up.

[eduardoschweitzer]

I'd love to see a video about the Navier-Stokes equation. Great video btw

[knowledgeseeker]

Please do a video on Magnetic Vector and Scalar potential.

[SudhirKumar-jxjj]

Hi Parth
Please make a video on the concept of Tensors.

[genelynlinsagan]

Thanks for a hard work and i have learn more

[Ottmar]

I like this definition of thermodynamic work better (Principles of Thermodynamics, Ansermet & Brechlet, 2019).
1.- For every system, there is a scalar extensive state function called energy (E). When
the system is isolated, the energy is conserved.
2.- When the system interacts with its environment, the energy evolution results from
the power of the processes exerted on the system.
3.- PW represents the mechanical power associated with the work performed by the
environment on the system that results in a deformation of the system without any change
in its state of motion, in particular its kinetic energy.
I really suggest you this book. I also really like Thermodynamics: Principles and Applications by Ismail Tosun. It's more engineering oriented, but it has great explanations and intuition.

[mikeb]

Really great. Clearly defined. And you're very, very easy to watch and listen to. (You remind me of one of my favorite internet science teachers-- Dr Mike of Dr Matt and Dr Mike. In my book, that's a huge compliment.)

THE FOLLOWING IS MY

I have a question about the box with the fire under it. The molecules in the box would vibrate, and then the molecules in the air surrounding the box would vibrate-- those things would be the transfer of heat. Right?

But the box might also start to shake and move. Would that be work?



Thank you again for the great video. I look forward to watching others. (And I also want to thank for the animations. I wish more chemistry videos would use them, since movement is at the heart of so many chemical, biological and physiological phenomena.

[ClemoVernandez]

thermodynamics I think has the most conventions which make it difficult to understand even if the phenomenon is really intuitive

[VaradMahashabde]

Heat : energy transfer we couldn't be bothered to track directly
Work : energy transfer, but not heat

Edit : one could say that the varibales regarding heat are distributed boltzmannly

[avirupbose]

Thanks for defining them. Most of people think heat and work done on the system are same 👍👍👍

[klawtawar]

My kid name is also Parth and he likes to watch your videos, thanks for making this videos.

[priyadarshiniacharya]

Parth i love your channel very much.Have been following your work since you were at 6k.

[remidanvin]

Ok this was good definition of what it cover but I was expecting more about thermodynamics. But well done to find the time to do these videos.

[YathishShamaraj]

The explanation was quick and simple love it Bro 👍♥️

[sagittarius]

Great job specially work was great
schools need to be like this :)