#ABSOLUTE ENTROPY FORMULA FREE#

The conservation of Gibbs free energy does not suddenly break down because we stop (or start) looking. Sure, we can use Shannon's formula in some cases, which is really just Boltzmann's formula with different units.Įntropy is a thermodynamical property of a bit of stuff, regardless of what we know about it. Entropy itself is whatever it is even before we bother calculating it, and we can estimate it different ways. > EDIT2 : A specific example where both the Thermodynamic entropy and the Shannon entropy can be experimentally seen to be equivalent :Įntropy goes to zero when spins align, but it does not mean that entropy is non-zero until we check that the spins are aligned. Knowing something does not change the state of the system you are observing. Basically, your interpretation is that 'we know a lot about the system, therefore entropy is low', whilst in a physical system it's the other way around: 'entropy is low, therefore we know a lot about it'. There is indeed some overlap (I have personally worked for a couple of years on applying information theory to calculate entropy in glass-forming materials), but not enough that you can just apply random concepts from one field to the other. However, there is tremendous overlap between the two camps. > Very roughly speaking, the items higher on the list can be assigned to the “information theory” camp, while the items lower on the list can be assigned to the “thermodynamics” camp. I am not impressed with that website in general, but in this instance I don't see anything wrong with that section. If you define a macrostate in such a way as it can have only one microstate, then yes, entropy is 0.

There are lots of caveats, asterisks, and cases that look like exceptions that’s a quick and dirty description. It is impossible to measure an absolute entropy in general (in the same way as it is impossible to measure an absolute energy in general). What we can do usually is measure how much something heats when we give it energy, and work from there to deduce any entropy change using equations from thermodynamics or statistical Physics.

In non-isolated systems, anything goes and entropy can go up or down locally all the time. they cannot exchange energy with anything else), entropy cannot decrease on average. Ordered states (like crystals) have lower entropies than disordered states (like liquids), because there are fewer ways of arranging atoms and still get a crystal compared to the combination of possible positions for each atom in a liquid. Entropy is how many of such states are possible. In a physical system it is related to how many arrangements of atoms/molecules/things there can be that would result in the system being in the state you can see.Įnergy tells you how difficult it is to put a bunch of particles (atoms, for example) in a given state. This is because a system at zero temperature exists in its ground state.It’s not a stupid question at all. In 1973 Bekenstein suggested ln ⁡ 2 0.8 π ≈ 0.276 cannot go to zero is analogous to the third law of thermodynamics, which states that the entropy of a system at absolute zero is a well defined constant. In 1972, Jacob Bekenstein conjectured that black holes should have an entropy, where by the same year, he proposed no-hair theorems. The increase of the entropy of the black hole more than compensates for the decrease of the entropy carried by the object that was swallowed. If black holes carried no entropy, it would be possible to violate the second law by throwing mass into the black hole. The second law of thermodynamics requires that black holes have entropy. As the study of the statistical mechanics of black-body radiation led to the development of the theory of quantum mechanics, the effort to understand the statistical mechanics of black holes has had a deep impact upon the understanding of quantum gravity, leading to the formulation of the holographic principle.

In physics, black hole thermodynamics is the area of study that seeks to reconcile the laws of thermodynamics with the existence of black hole event horizons.

Absolute entropy formula