Why is the sign convention of work opposite in physics and chemistry? This only makes matters more complicated. Why did the scientists have to do this? Is there even any reason behind this? Sign Convention

  • $\begingroup$ Get used to it. This is just one example of many. Some scientists consider tensile stress as positive and some consider compressive stress as positive, for example. $\endgroup$ Apr 16, 2021 at 11:58
  • $\begingroup$ "Why did the scientists have to do this?" You made my day, thanks. I think it's not much of a generalization to say that in science conventions are constantly there to make your day hard, whichever field you work on. You'd hope there would be a striving effort to standardize these choices universally, but then you go to the literature and often find the opposite. Unfortunately, such is life. $\endgroup$
    – secavara
    Apr 16, 2021 at 12:00
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    $\begingroup$ Does this answer your question: chemistry.stackexchange.com/questions/66088/…. $\endgroup$
    – Bob D
    Apr 16, 2021 at 12:47
  • $\begingroup$ OK @secavara, you can have your way. Whichever choice you like best, we in other disciplines have decided to standardize for everyone on the other choice. How does that make you feel? $\endgroup$ Apr 16, 2021 at 13:36
  • $\begingroup$ The shown convention for physics is not really consistent. In thermodynamics and mechanics you might see it differently. Personally I like the intuitive idea of "positive energy is added energy", so that work done on a system (providing more energy to the system) is positive. But it really doeneds on the typical usage in various fields of science and engineering. $\endgroup$
    – Steeven
    Apr 16, 2021 at 13:51

1 Answer 1


It is a matter of convention in a specific community, which typically arose by accident, like many other things. Just to give a few examples:

  • writing the complex exponent $e^{\pm i\omega t}$
  • where to keep $2\pi$ in Fourier transform
  • whether one rotates the coordinate system or whether one rotates in rotation transformations

It is by far more complicated for many people to agree to use the same notations, conventions, definitions.


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