How does knowing the density of water help us in the science class?

The density of seawater plays a vital role in causing ocean currents and circulating heat because of the fact that dense water sinks below less dense. Salinity, temperature and depth all affect the density of seawater. Density is a measure of how tightly a certain amount of matter is packed into a given volume

Explanation:

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.