0. No heat flows between two bodies at the same temperature.

1. All Energy is conserved.

2. Heat always flows downhill.
Disorder is also created in temperatures greater then Absolute Zero.

3. Absolute Zero cannot be reached.

OR (as the ever helpful physicist C.P. Snow remarked)

1. You cannot win.
2. You cannot break even
3. You cannot leave the game.
A little better summary:

### The first law of Thermodynamics

The total amount of energy in the universe is constant, energy cannot be created nor destoryed, it can merely be changed from one form to another. And if Einstein is correct, then this also means that matter can neither be created nor destroyed. Basically, we got what we got, and that's all we're gonna get.

In equation form:

DE = Q + W
Change in Energy = Heat Energy entering/leaving the system + Work Energy done by/on the system

### The second law of Thermodynamics

There are many ways to phrase this... My favorite way to think of it is that in any transfer of energy from one form to anther (for example, electrical to mechanical energy), useful energy is lost. Basically, you can't get out more than you put in, and you can't even get out what you put in.

The second law also states that the entropy (randomness) of a system will always increase, and it's impossible to decrease entropy without work. Basically, heat and energy tend to migrate from areas of higher concentration to areas of lower concentration, and it requires work to get it to go the other way.

### The third law of thermodynamics

This states that the entropy of a system will approach a constant value as the temperature decreases, and that the entropy of a pure crystal will be zero at a certain temperature (absolute zero).

### The Zeroth Law of thermodynamics

Not a true law, but a derivation of the second law. This states that if two systems are in equilibrium with a third system, then they must be in equilibruim with each other. For example, if two containers of water are at the same temperature as a third, they must both be at the same temperature.

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