It is Law

The second law of thermodynamics, also known as the law of entropy, states that order will always decrease and chaos will rise. Entropy can also be used as a unit of measure for energy that is no longer capable of affecting a closed system; closed system meaning a system that is not losing energy, nor gaining.

For example, friction in the atmosphere is produced by gas molecules colliding with one another as well as the Earth, thus creating disorderly energy. Another more practical example is ice melting into water. In order for this to occur, bonds between the water molecules must be altered; hence, order turning into chaos. An additional example is the decomposition reaction of hydrogen peroxide. When H2O2 decomposes, two other molecules produced: water and oxygen gas. To visualize entropy, let's picture a mug of hot coffee. You want to drink this coffee as soon as possible because you are incredibly tired and need to prepare for the long day of work ahead of you. You can either a) add cold cream to your coffee and wait 5 minutes or b) wait 5 minutes and then add cold cream. With a thorough understanding of the law of entropy, it would be most logical to wait 5 minutes first because the initial difference in temperature between the air and the coffee is greater, thus resulting in a higher rate of heat transfer. If you were to add cream at the beginning, the temperature would be a lot cooler and the difference would be a lot smaller, resulting in a slower rate of heat transfer. Overall, entropy is obeyed when there is a change of state, formation of energy, and/or the number of molecules.

Ironically, to achieve orderly energy, there must be disorder. Therefore, so long as the amount of orderly energy is less than the amount of disorderly energy, then the second law of thermodynamics stands true.