What is Entropy?

What is Entropy?

    Entropy is usually described as the measure of molecular disorder in a system. As a system becomes more disordered the molecules position becomes less predictable and the systems entropy increases. An example of entropy increasing in a system is when ice water melts into liquid water. The molecules have more energy, are free to move more and therefore are more disordered.

    The second law of thermodynamics states that energy of all kinds will disperse or spread out in a system provided it is not prevented from doing so. Entropy is the quantitative measure of this spontaneous process. This also means that processes must proceed in a direction in which the generated entropy of the system increases. The entropy change of a system can be negative but the generation of entropy must be positive. Water obviously can freeze into ice at low temperatures but it is the surroundings in this example have an increase in entropy greater than the decrease in the water.