Pure water is an odorless and tasteless liquid. It has a blue hue, which can only be detected in layers of great depth, so, in principle, it is considered colorless. At normal atmospheric pressure, the freezing point of water is 0 ° C and its boiling point is 100 ° C. Water reaches its maximum density at a temperature of 4 ° C and expands upon freezing.
On Earth, water is the only substance that exists at ordinary temperatures in the three states of matter, that is, solid, liquid and gas. It is in a solid state in glaciers and polar ice caps. It exists in a liquid state in the rain clouds and in the form of dew in the vegetation. In addition, it covers three quarters of the earth's surface in the form of swamps, lakes, rivers, seas and oceans. As gas, or water vapor, it exists in the form of fog, steam and clouds.
Due to the influence of gravity, water accumulates in the interstices of the rocks below the earth's surface, forming underground water reservoirs that supply wells and springs, and maintain the flow of some streams during periods of drought.
In this chapter:Water and marine relief: The surface of the globe covered by water is greater than that corresponding to emerging land… Read page Movements in seas and oceans: The enormous body of water that forms the seas and oceans of the Earth is subject to movements de… Read page Sea currents: The largest surface ocean currents in the world are caused by the prevailing winds… Read page Earth's oceans and oceans: The mass of the waters that cover the depressions of the earth's crust forms seas and oceans, which… Read page Islands: Islands are usually defined as portions of land surrounded by water, although it is true that in this definition ... Read page Islands: oceanic, continental, volcanic, coral: There are islands of various types, depending on their origin. They can be volcanic… Read page Surface waters: Rivers: The waters that run through the surface of the emergent lands are very important for the beings… Read page Underground waters: Formerly it was believed that the underground waters came from the sea and had lost their salinity when leaking ... Read pageThe surface waters: Lakes: The lakes are masses of fresh or salt water that are surrounded by land ... Read pageThe glaciers: The great masses of ice that cover the planet's poles and the highlands of the world's great mountain ranges are … Read page