Ice is a solid substance that is in a state of aggregation, which tends to have a gaseous or liquid form at room temperature. The properties of ice began to be studied hundreds of years ago. About two hundred years ago, scientists discovered that water is not a simple compound, but a complex chemical element consisting of oxygen and hydrogen. After the discovery, the water formula began to look like H2O.
The structure of ice
H2O consists of two hydrogen atoms and one oxygen atom. At rest, hydrogen is located at the tops of the oxygen atom. Oxygen and hydrogen ions should occupy the vertices of an isosceles triangle: oxygen is located at the top of a right angle. This structure of water is called a dipole.
Ice is 11.2% hydrogen and the rest is oxygen. The properties of ice depend on its chemical structure. Sometimes it contains gaseous or mechanical formations -impurities.
Ice is found in nature in the form of a few crystalline species that stably retain their structure at temperatures from zero and below, but at zero and above it begins to melt.
Crystal structure
The properties of ice, snow and steam are completely different and depend on the structure of the crystals. In the solid state H2O is surrounded by four molecules located at the corners of the tetrahedron. Since the coordination number is low, the ice may have an openwork structure. This is reflected in the properties of ice and its density.
Ice shapes
Ice is one of the most common substances in nature. On Earth, there are the following varieties of it:
- river;
- lake;
- maritime;
- firny;
- glacial black;
- ground.
There is ice that is directly formed by sublimation, i.e. from the vapor state. This view takes on a skeletal form (we call them snowflakes) and aggregates of dendritic and skeletal growth (hoarfrost, frost).
One of the most common forms are stalactites, i.e. icicles. They grow all over the world: on the surface of the Earth, in caves. This type of ice is formed by the flow of water drops at a temperature difference of about zero degrees in the autumn-spring period.
Formations in the form of ice strips that appear along the edges of reservoirs, at the border of water and air, as well as along the edge of puddles, are called ice banks.
Ice can form in porous soils in the form of fibrousvein.
Ice properties
Substance can be in different states. Based on this, the question arises: what property of ice is manifested in a particular state?
Scientists identify physical and mechanical properties. Each of them has its own characteristics.
Physical properties
The physical properties of ice include:
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Density. In physics, an inhomogeneous medium is represented by the limit of the ratio of the mass of the substance of the medium itself to the volume in which it is enclosed. The density of water, like other substances, is a function of temperature and pressure. Usually, a constant density of water is used in calculations, equal to 1000 kg/m3. A more accurate density indicator is taken into account only when it is necessary to make calculations very accurately due to the importance of the result of the density difference.
When calculating the density of ice, it is taken into account which water became ice: as you know, the density of s alt water is higher than distilled water.
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Water temperature. Usually water crystallization occurs at a temperature of zero degrees. Freezing processes occur in jumps with the release of heat. The reverse process (melting) occurs when the same amount of heat is absorbed that was released, but without jumps, but gradually.
In nature, there are conditions under which water is supercooled, but it does not freeze. Some rivers remain liquid even at -2 degrees.
- Heat capacity. This is the amount of heat that is absorbed when the body is heated for eachdegree. There is a specific heat capacity, which is characterized by the amount of heat required to heat a kilogram of distilled water by one degree.
- Compressibility. Another physical property of snow and ice is compressibility, which affects the decrease in volume under the influence of increased external pressure. The reciprocal is called elasticity.
- Ice strength.
- The color of ice. This property depends on the absorption of light and scattering of rays, as well as on the amount of impurities in the frozen water. River and lake ice without foreign impurities is visible in pale blue light. Sea ice can be completely different: blue, green, blue, white, brown, have a steely tint. Sometimes you can see black ice. It acquires this color due to the large amount of minerals and various organic impurities.
Mechanical properties of ice
The mechanical properties of ice and water are determined by the resistance to the external environment in relation to a unit area. Mechanical properties depend on structure, salinity, temperature and porosity.
Ice is an elastic, viscous, plastic formation, but there are conditions under which it becomes hard and very brittle.
Sea ice and freshwater are different: the former is much more plastic and less durable.
When ships pass, the mechanical properties of ice must be taken into account. It is also important when using ice roads, crossings and more.
Water, snow and ice havesimilar properties that define the characteristics of a substance. But at the same time, many other factors influence these readings: ambient temperature, impurities in the solid, as well as the initial composition of the liquid. Ice is one of the most interesting substances on Earth.
