〈 Berger | Dillon 〉

Four years after taking a thermo course and I finally understand what the hell the partial derivative notation in thermodynamics means I think

i asked early on .. it just means to hold the subscripts constant .. but isn't that what a partial derivative means anyways? it's kind of an over-clarification that makes it somewhat confusing tho i understand why they do it

It’s the mixture of different disciplines and their notations. I’m still learning to speak engineer mathematically. As with your partials point, my assumptions never seem clear to non-physics people. Also I never groked thermo UNTIL I learned stat mechanics.

I have a little page of lecture notes in which I explain to students that Maxwell relations (which I struggled with) are just identities of partial derivatives. It is delightful to see the dawn of understanding in their eyes.

I still find the minus sign in dx/dy * dy/dz * dx/dx = -1 slightly surprising. (Sorry, don't know how to coerce a partial derivative operation on this keyboard.)

Really messes with the whole “derivatives are fractions” thing

Yep. Ordinary derivatives behave a lot like fractions. Partial derivatives don't.