How does temperature affect the density of water?

Higher temperatures decrease water density due to the unique properties of water as a substance. As water is heated, its molecules gain kinetic energy and move apart from each other, which leads to an increase in volume without a corresponding increase in mass. This expansion results in lower density because density is defined as mass per unit volume.

In contrast, colder water has molecules that move more slowly and are more closely packed together, leading to a higher density. This is particularly significant in the context of aquatic environments, where variations in temperature can create layers of water with differing densities, impacting the movement of water and the organisms living within it. Understanding this relationship is crucial for studying ocean currents, thermal stratification, and the distribution of marine species.