The Second Law of Thermodynamics states that in any energy transfer or transformation, the total entropy of a closed system will always increase over time. Entropy is a measure of disorder or randomness, meaning that natural processes tend to move towards a state of greater disorder. This principle explains why energy tends to disperse and why systems become less organized without external intervention. In practical terms, the Second Law implies that it is impossible to convert all energy from one form to another without some loss of energy, usually as heat. This is why machines, like engines, cannot be 100% efficient, as some energy is always lost to the surroundings, increasing the overall entropy of the universe.