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I am currently confused by the term heat. I had studied that work is a way of transfer of energy so is heat. But the point of confusion is that what is the difference between these two? What I can think of as a difference between these is that one(work) increase energy of an object in a particular direction whereas the other (heat) increases it in random direction (though I doubt that this may be true). If this isn't the case then what really is the difference between these two?

This answer here answers my question.

  • Related: https://physics.stackexchange.com/a/431401/520 Possible duplicates: https://physics.stackexchange.com/questions/141089/difference-between-heat-and-work?rq=1 https://physics.stackexchange.com/questions/428009/what-is-the-differentiating-factor-between-work-and-heat?rq=1 – dmckee --- ex-moderator kitten Dec 13 '19 at 15:49
  • @dmckee I was looking for such answers as yours. Thanks! –  Dec 13 '19 at 15:56
  • There are two ways to exchange energy with the system either thermally (by exchanging heat) or mechanically (by doing work). – SRS Jan 03 '20 at 09:52

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All of the links given are good answers. Since sometimes a different explanation may work best for someone, I offer the following.

Heat is energy transfer between objects (solids, liquids or gases) due solely to a temperature difference between the objects.

Work is energy transfer between objects due to a net force exerted by one object on another through a distance, or displacement.

Heat $Q$ and work $W$ are related to the change in internal energy $\Delta U$ of a system (solid, liquid or gas) by the first law of thermodynamics which can be written, for a closed system (no mass transfer) as

$$\Delta U=Q-W$$

Where $Q$ is positive for heat added to the system and $W$ is positive for work done by the system.

Think of a change in internal energy of a system as a change in the energy account balance due to energy transfers into or out of the account. Heat $Q$ transferred into the system or work $W$ done on the system are energy deposits, i.e., they increase the internal energy of the system. Heat transferred out of the system or when the system does work on something outside the system are energy withdrawals, i.e., they decrease the internal energy of the system.

Hope this helps.

Bob D
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