Water is one of the main substances that ensure the existence of the planet and humanity. This is a completely unique element, without which the life of any living creature is impossible. Some chemical and physical properties of water are unique.
The importance of this substance is difficult to overestimate. Water occupies most of the planet, forms oceans, seas, rivers and other bodies of water. She is directly involved in the formation of climate and weather, thereby ensuring certain conditions of existence in a particular corner of the planet.
For many organisms, it serves as a habitat. In addition, almost every living creature in one way or another consists precisely of water. For example, its content in the human body is from 70 to 90 percent.
Physical properties of water: a brief description
The water molecule is unique. Its formula is probably known to everyone: H2O. But here are some of the physical properties of water that directly depend on the structure of its molecule.
In nature, water exists immediately in three states of aggregation. Under normal conditions, it is a liquid substance without color, odor and taste. When the temperature drops, water crystallizes and turns into ice. With increasing temperature, the liquid passes into a gaseous state - water vapor.
Water is characterized by a high density, which is about 1 gram per cubic centimeter. Boiling water occurs when the temperature rises to one hundred degrees Celsius. But when the temperature drops to 0 degrees, the liquid turns into ice.
Interestingly, a decrease in atmospheric pressure causes a change in these indicators - water boils at a lower temperature.
The thermal conductivity of water is approximately 0.58 W / (m * K). Another important indicator is its high surface tension, which is almost equal to the corresponding indicator for mercury.
Unique physical properties of water
As already mentioned, it is water that ensures the normal existence of the planet, affecting the climate and vital functions of organisms. But this substance is actually unique. It is these amazing properties of water that provide life.
Take, for example, the density of ice and water. In most cases, when freezing, the molecules of substances are closer to each other, their structure becomes more compact and denser. But this scheme does not work with water. This amazing property was first described by Galileo.
If you slowly lower the temperature and monitor the freezing of water, then at first the scheme will be quite standard - the substance will become denser and more compact. Changes will occur after the temperature reaches +4 degrees. With this indicator, water suddenly becomes lighter. That is why ice floats on the surface of the water, but does not sink. By the way, this feature ensures the survival of aquatic life - water rarely freezes completely, preserving the life of its inhabitants.
By the way, when freezing, the substance expands by about 9%. This feature of water causes natural corrosion of rocks. On the other hand, the water pipes are therefore burst when unexpected cooling.
But these are far from all the interesting properties of water. Another unique feature is the abnormally high heat capacity. For example, the amount of heat needed to heat one gram of water per degree is enough to heat about 10 g of copper or 9 g of iron.
The entire oceans is a global thermostat that smoothes temperature fluctuations, both daily and annual. By the way, water vapor, which is contained in the atmosphere, is endowed with the same properties. It's no secret that the desert is characterized by sharp temperature changes - it is too hot during the day and very cold at night. This is due precisely to dry air and the lack of the required amount of water vapor.