An increase in entropy refers to an increase in the amount of disorder or randomness in a system. The best illustration of an increase in entropy can be seen in the mixing of gases. When gases are mixed, the particles become more randomly distributed, and their movements become more disordered, resulting in an increase in entropy.
On the other hand, freezing of water, the condensation of vapor, and solidifying of candle wax are all processes that involve a decrease in entropy. When water freezes or vapor condenses, the particles become more ordered, resulting in a decrease in entropy. Similarly, when candle wax solidifies, the molecules become more tightly packed, resulting in a decrease in entropy.