Second law of thermodynamics: Every energy transfer or transformation increases the entropy of the universe since all energy transfers result in the loss of some usable energy. Entropy: A measure of randomness and disorder in a system. Energy is the capacity for doing work, generating heat, and emitting light. Entropy: The measure of the level of disorder in a closed but changing system, a system in which energy can only be transferred in one direction from an ordered state to a disordered state ”. Entropy is the loss of energy to do work.