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treeses t1_j9veqsm wrote

Reply to comment by Coomb in why is sign convention for work different on chemistry and physics? by Melodic-Recipe2618

That does seem like a nice pedagogical step. You still get the same sign for enthalpy though, regardless of which convention you use. My observation was really just that, it isn't a meaningful convention in terms of the results you get. (Unlike, say, using a convention that current is the flow of negative charge carriers, which would change all sorts of signs all over the place. That would be crazy...)

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Coomb t1_j9wg3jb wrote

You're right. The positive or negative sign in that expression is just a bookkeeping convention and doesn't really have any further consequences. In some sense, it's a one-dimensional problem (the "heat dimension"). An EM analog might be nodal current analysis. For the purposes of analyzing nodal currents, it doesn't actually matter if you say that the sum of all the currents is zero, or if you say that the sum of currents flowing in, minus the sum of currents flowing out, is zero (and call all of the currents positive). In either case, you're preserving the information about whether something is going in or going out, just with a different system of bookkeeping -- are the negative signs attached to each current individually, or a group of currents that you identify and sum?

Once you start involving multiple spatial dimensions, as is common in EM problems, of course your choice of sign convention has more implications downstream.

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