0th Law of Thermodynamics

The 0th law states that if object A is equal to object B and object B is equal to object C then objects A and C are equal.


This is not a super important rule, it was just created to make the next couple of rules possible. It is just stating the transitive property. If A=B and B=C then A=C; it's pretty much common sense.

1st Law of Thermodynamics

This law says that energy can be transferred from one system to another in many forms. Also, energy can't be created or destroyed.


It is also called the law of conservation of energy. It can be expressed with the equation W=ΔE. This law explains the amount of work that goes into a system.

Second Law of Thermodynamics

This law states that you cannot finish a physical process with as much useful energy as you started with. Some is always wasted.


This law is saying that entropy or "randomness" always increases in a closed system. Or in other more general terms, energy is always wasted. As stated in the first law, the quantity of energy will always remain the same, but the quality of energy will change. When energy is changed into heat, it is pretty much useless because it cannot be used for anything. The quality of it went down. According to this law, we will eventually run out of useable energy.

Third Law of Thermodynamics

This law states that absolute zero only exists in perfect crystal.
Since perfect crystal is very ideal, therefore, absolute zero does not exist.


Heat and entropy(disorderliness) are related. As you lower the temperature of something, its entropy will decrease but it could not be 0.