The Earth is a unique planet in that it is covered by more than 70 percent water. There are several properties of water that mak

The liquid water, being denser, offers better protection from cold air for organisms in comparison to the ice, which has lower density. This density variation prevents lakes and seas from freezing completely, as a less dense layer of ice forms at the surface, acting as a thermal insulator that keeps the water beneath it liquid. This is essential for the survival of aquatic plants and animals. Ice serves as an insulator due to its specific heat of 2.03 J/g. ºC, which is lower than that of water at 4.18 J/g. ºC. Once winter passes and warmer weather arrives, the surface ice melts easily, which would not occur if the ice sank to the bottom; such a scenario would threaten the survival of aquatic life. Additionally, liquid water achieves its maximum density at approximately 4ºC (1,000 g/cm3). During seasonal transitions like spring and fall, water reaches temperatures close to this point, becoming denser and sinking, which creates convection currents that help distribute nutrients throughout the water.

The liquid water, which is denser, provides better insulation against cold air for organisms than the less-dense ice.