Thermodynamics 4 - Heat Engines and Entropy

This is the fourth video in the Thermodynamics sequence. First we talk about Heat Engines, which are powered by heat input and provide work as output. They are represented by PV diagrams which exhibit a positive net work and positive net heat. A key fact is that, in addition to work, heat engines also output waste heat energy. It turns out to be impossible to avoid this waste heat. We can characterize how much waste heat is produced using the efficiency formula for the engine. After introducing the concept of Entropy, we find that there is a maximum efficiency for any engine, and that this maximum is always less than one.

Entropy is traditionally a confusing topic. The physical picture behind entropy involves somewhat sophisticated subjects, like microstates/macrostates and order/disorder, that are a bit removed from the issues at hand. We won't discuss the physical meaning of entropy here, but merely state some facts about it and use those facts to do some calculations. While the microstate definition of entropy is very important, it would carry us too far afield to go over in this video.

This video is part of a series on introductory topics in physics. The target audience is beginning college students who have already had one semester of Newtonian Mechanics.

Check my channel for more!

Category:

Education

Tags:

• entropy
• thermodynamics
• heat
• engine
• carnot
• physics
• lecture
• review
• efficiency
• introduction
• reversible
• irreversible
• isothermal
• adiabatic
• isobaric
• ideal
• gas
• work
• temperature

[joseantara]

@HPaisana Maybe he's a soldier on tour trying to do some school...? Good job.

[HPaisana]

@AmericaGodbless you live in iraq and have americagodbless as nickname... shame for your terrorists

[AmericaGodbless]

Man you are better than our pro here in Iraq