Can you tell me what is thermodynamics? and describe me the zeroth law of thermodynamics and the three laws?

Answer 1

Thermodynamics is the study of the macroscopic properties of systems that are statistical in nature at the microscopic level. For example, it covers the study gases, with properties of heat, energy, volume, pressure, etc., but the methods can be applied to more esoteric fields such as quantum gravity. A quick review of the first 3 laws including the 0th one:

0th Law: If object A and object B are in thermal equilibrum with object C, then object A and object B are also in thermal equilibrum with each other. In other words, they'd all have the same temperature.

1st Law: Energy is conserved, so that if object A does work W while heat H is applied to it, the internal change of energy in A equals H - W, or heat energy in less work energy out.

2nd Law: The total entropy of any closed system will only increase over time, never decrease, until it reaches a maximum when the closed system reaches equilibrum. Entropy is a complex subject, best explained in statistical mechanics. This law places fundamental limits on what thermodynamic engines can do.

3rd Law: Entropy is 0 only when the temperature of a closed system is at absolute 0. Interestingly enough, because of quantum properties, not usually covered in thermodynamics, the total energy of such a system is not necessarily 0, but that's another story.

Answer 2

The zeroth law of thermodynamics:

If A is the same temperature as B

And B is the same temperature as C

Then A is the same temperature as C