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
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.
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.
@@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.
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_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.
@@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😅
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.
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
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!
@@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)
Awesome visual examples and simplified to absorb the information being released, making understanding and keeping it in so much easier. Thank you, Prof. Dave!
Different disciplines will prefer different sign conventions. I'm accustomed to the heat engine sign convention, where work done by the system is positive.
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
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.
Please note that you have incorrectly applied the signs for work. Work is (-) when it is done by the system on the surroundings. Work is (+) when it is done on the system.
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
@@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 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
my prof. puts links to ur videos and that means 2 things 1. he knows nothing about chemistry which he actually doesn't(don't ask) 2. u r way better than him to the point we watch YT videos in lectures instead of him doing his f job 🙂
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...😀
Hey quick question for those interested. How much do you need to cool a solar cell operating at, let's say, 23% efficiency? My thoughts are that a solar cell should not change its internal energt U, so in other words deltaU or dU/dt should be 0. So 23% of the solar energy becomes electrical work, while the rest of the sun's power (1-0.23=0.77) is transferred as heat that, without cooling, would accumulate in the solar cell. In order for dU/dt (delta U) of the solar cell to be 0 you need to fulfill Q=W, so in other words you need to cool the cell to such an extent that the only heat that isn't cooled off equals the electrical power of the solar cell, in this case 0.54 times the power of the sun? Is this way of thinking correct? I would very much appreciate any input.
Yes, indeed, that is correct. This is why the panels heat up, if you turn off the system and make them remain at open circuit. The lack of a destination for the power to go, means that they heat up to a temperature where they can radiate more energy to the background. This is counterintuitive, because most of the time, operating electrical equipment makes it heat up, rather than cool down.
Hello Dave ! can you tell me where can I get easy explanations about applied thermodynamics engineering please for 2nd year university ?? I don't find any ressource worth of watching on internet
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Sometimes hearing the same information from a different person helps very much!
I agree with you.
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
you just wrote the same convention pair twice.
يا رجُل ماهذا الشرح الجمييييل ، شرح مُبسط وجميل ♥️♥️♥️♥️👏🏻👏🏻👏🏻
كملتي معه ولا ؟ عندي اختبار بكره.
I swear to study thermodynamics eagerly if he's my professor.Deserves a lot of subscribers and likes.
Why couldn’t you have been my professor in college? You explain everything perfectly!
U should do study
My girl 😂😂
Yes
You study this in college. We study this is in 10th grade in asia💀☠️☠️
@@jefrreyjeffery2192 We study this in college too, we do more than this, but I'm coming back to the basics, Also Asian here.
@@anuragchaudhary6307maybe you two live in two different countries/regions
,after all Asia is a big place
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.
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.
Yes, video is telling wrong about the sign conventions.
@@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.
Yes work done on the system is positive, work done by the system is negative
Well the sign convention don't matter much as long as they are opposite in any case
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.
This is my confusion too... When to use which one?
@@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.
@@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😅
Professor Dave is definitely still saving educational lives years later with these videos
i want all Teachers as you. You explain a lot of things in few minutes.Thank you..
As always, clear, and most importantly, concise. No wasted words or time. Well done, Professor Dave
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 ....
Best video for understanding the concept
Professor Dave helping me cram for the physics GRE, what a hero
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.
You're making me fall for thermodynamics.
Thank you so much
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
We need more professors like you in India ...
Exactly
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!
thank you so much. i thought i was going crazy.
@Mohamed Sherif how is that so?
@@na-chan163 the surrounding energy is the atmosphere's energy and the system's energy is the internal energy
Fatima Isra work done by system (expansion) is negative for chemistry but positive for physics. Can you pls explain this?
@@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)
I think I'm dropping thermodynamics
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Good one 😂
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IUPAC said that work done by the system is negative and vice versa
Everyone wathing this video please do note that the sign convention used here is only valid for physics, it is the opposite for chemistry.
Awesome visual examples and simplified to absorb the information being released, making understanding and keeping it in so much easier. Thank you, Prof. Dave!
You deserve to be a noble prize winner. Sir you are awesome you should get a noble prize!!!!!
Anyone else got exam today GL Guys also Professor Dave u a life savour
I wish your channel was bigger
me too, friend!
It is now
Now it's bigger than ever!!!
@@ProfessorDaveExplains that's amazing
and could you explain why U become zero when temeperature is constant plz ?
***My chemistry teacher has told me +w=work done on system, -w=work done by system
Different disciplines will prefer different sign conventions. I'm accustomed to the heat engine sign convention, where work done by the system is positive.
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
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.
Sir you have done wrong here about sign convention work done by the system is negative and work done on the system is positive
That's chemistry. This is a physics tutorial.
@@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
@@makeitmemorable__ lol same
Why does this channel have so few subscribers???!! You're amaze man! Thanks! ❤
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.
Right 👍
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.
Please note that you have incorrectly applied the signs for work. Work is (-) when it is done by the system on the surroundings. Work is (+) when it is done on the system.
No, that's for chemistry. This is a physics tutorial.
I'm really impressed , the way of teaching, how u remember all those things, can u give me any tips to remember easily
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.
When work is done by the system W is negative when work is done on the system w is positive
You said the opposite
Chemistry and physics have opposite conventions. This is a physics tutorial.
@@ProfessorDaveExplains ahh so that's why
thank you
man... u r the best one explain this .........so thank u
Thanks for your brilliant explanation
3:49 isn’t if the work done by the system then it is negative?
You do an amazing job ♥ !
why was (150J) taken positive ??? In the Last Example.?
Isnt work negative when it is performed by the system or am i trippin?
@ProfessorDaveExplains
thank you now i understanding therom esay.
I really wish I had a physics tutor like this. Unlucky me
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
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)
Thanks sir.we are hoping to a vedio on minerals .
بارك الله فيك...
God bless you
Whew this is a lot to remember
I think there are mistake in work subject
thank you sir.
I didn't skip the ad😎😌
how about isobaric
short and easy to understand thanks
Question: Why must heat be represented by "Q" and internal energy is to be represented by "Delta U"?
delta U means the overall change in internal energy. delta U= U2 - U1
@@heinzguderian9572 but why use U specifically?
@@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
@@heinzguderian9572 The letter U I mean
@@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
Sir your way of explaining topic in detail is the #best.....
Great video! This helped me a lot!
3:27
Is it correct?
Work done on the system is +ve
And
Work done by the system is -ve
Correct me ......
If I am wrong
Thank you for making this video.
Well Explained.
It Helps me a lot.
THANK YOU PROF!!!!!!!!!!!!!!!!
Professor Dave is amazing, honestly!
you saved me Mr!lots of thanks from Ethiopia
my prof. puts links to ur videos and that means 2 things 1. he knows nothing about chemistry which he actually doesn't(don't ask) 2. u r way better than him to the point we watch YT videos in lectures instead of him doing his f job 🙂
Amazing sir 👌
Wish you have more successful in life
Thakyou professor dave!
Thankyou Professor
Wow. Thank You
Thanks dave
Nice video Dave, really helped me and my buddy Johan learn thermodynamics :)
please make a video on carnot engine or carnot cycle
that would be the second law, the one right after this!
Exordinary, congratulations, Sir
Excellent for revision, short and crisp, covers all points quite well. Thanks a bunch. I also love your organic chemistry and dna-rna videos.
man i wish you were my professor
very good expression sir!
Thanks a lot sir!
You made it easy
Love to hear more from you
I loved this video. so much good information!
Thanks.
thankyou sir, it is very useful for me
Thank you so much!
awesome, great job professor .
keep on
From college of science
azhar university ❤ from Egypt 🇪🇬
Thanks
Thinking I've understood and still failing comprehension question😭😂Lord do me Mercy 🤲
Good
Thanks physics
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...😀
Hey quick question for those interested. How much do you need to cool a solar cell operating at, let's say, 23% efficiency?
My thoughts are that a solar cell should not change its internal energt U, so in other words deltaU or dU/dt should be 0. So 23% of the solar energy becomes electrical work, while the rest of the sun's power (1-0.23=0.77) is transferred as heat that, without cooling, would accumulate in the solar cell.
In order for dU/dt (delta U) of the solar cell to be 0 you need to fulfill Q=W, so in other words you need to cool the cell to such an extent that the only heat that isn't cooled off equals the electrical power of the solar cell, in this case 0.54 times the power of the sun?
Is this way of thinking correct? I would very much appreciate any input.
Yes, indeed, that is correct. This is why the panels heat up, if you turn off the system and make them remain at open circuit. The lack of a destination for the power to go, means that they heat up to a temperature where they can radiate more energy to the background. This is counterintuitive, because most of the time, operating electrical equipment makes it heat up, rather than cool down.
Tq very useful
Good explanation
Work done on the system its sign is positive while work done by the system its sign is negative
the convention is opposite for physics and chemistry
Ok sir
How it is possible?
In physics and chemistry both sign are same
no they are opposite conventions
Work is negative when work is done by the system, and vice versa
chemistry and physics have different conventions. this is a physics tutorial.
I am from India ❤️
Thank you!
If only you'd note the differences between chemistry and physics, would save us so much shock that we were taught wrong....
Thankyou!
Mr. Dave, you are awesome
thank you very much and wish you good future
Very great video
Hello Dave ! can you tell me where can I get easy explanations about applied thermodynamics engineering please for 2nd year university ?? I don't find any ressource worth of watching on internet
Why Q - W and not Q + W, but change the sign convention of work done to match that of Q?
Thanks a lot!