Ice is a solid substance, which is produced by the freezing of liquid water or water vapor. At temperatures down to 0°C, water vapor develops as frost at ground level and snowflakes (each consists of a single ice crystal) in the clouds. Below similar temperatures, liquid water produces a solid (solid ice), as, for example, sea ice, river ice, hail, and ice formed commercially or in the household refrigerators.
Occurrence
Ice occurs on the continents of Earth and the surface waters in various forms. Most notable are given as the continental glaciers (which are the ice sheets) that cover much of Greenland and Antarctica. Fewer masses of perennial ice, known as ice caps, occupy parts of Arctic Canada, including other high-latitude regions, whereas the mountain glaciers occur in more restricted areas, such as the flatlands below and mountain valleys. For more information on ice and its various forms, we can get it from many articles about ice.
The other occurrences of ice on the land are various types of ground ice, which are associated with permafrost, i.e., the permanently frozen soil common to most cold regions. In the polar regions of the oceanic waters, icebergs take palace when large masses of ice break off from ice shelves or glaciers and drift away. The seawater freezing in these regions results in the sheet formation of sea ice called pack ice.
During the winter season, similar ice bodies produce on rivers and lakes in several global locations. Ice in rivers and lakes, icebergs, glaciers, pack ice, and permafrost are treated separately. We can also know the detailed information on the widespread occurrences of glacial ice during the Earth’s past from various sources.
Structure of Ice
Ice or solid water is described as the solid-state of water (solid ice), which is a normally liquid substance that freezes to a solid-state (or solid state of water) at a temperature of 0 °C or below and expands to the gaseous state at a temperature of 100 °C or higher. Water is defined as a remarkable substance that is anomalous in virtually all of its physical and chemical properties and is literally the most complex of all the known single-chemical compounds.
The three-dimensional configuration of a water molecule can be visualised as a tetrahedron, with an oxygen nucleus in the centre and four legs with the possibility of a high electron. The two legs where the hydrogen nuclei are present are known as bonding orbitals.
Structure in Various Stages
In the liquid state, most of the water molecules are associated with a polymeric structure, which means molecule chains are connected by weak hydrogen bonds. Under the thermal agitation influence, there is a constant reforming and breaking of these bonds.
In the gaseous state, whether water vapor or steam, water molecules are largely independent of each other, and, apart from the collisions, their interactions are slight. Then, Gaseous water is largely monomeric, which it means, consisting of single molecules, although they rarely occur as dimers (union of two molecules), and even some trimmers (a combination of three molecules).
At the other extreme, in the solid-state, water molecules will interact with each other strongly enough to produce an ordered crystalline structure, with every oxygen atom collecting the four nearest of its neighbors and arranging them in a rigid lattice about itself.
The Ice Crystal
At standard atmospheric temperatures near 0 °C and pressure, commonly, the ice crystal takes the form of planes or sheets of oxygen atoms joined in an open hexagonal ring series. The axis, which is parallel to the hexagonal rings, is named the c-axis and coincides with the optical axis of the crystal structure.
Properties
Mechanical Properties
Like other crystalline solids, ice subject to stress undergoes elastic deformation, returning to its original shape when it is ceased by stress. However, if a shear force or stress is applied to a sample of ice for a very long time, first, the sample will deform elastically and will then continue to plastically deform, with a permanent shape alteration.
Optical Properties
Pure ice is very transparent, but air bubbles render it opaque somewhat. The absorption coefficient or the rate at which the incident radiation decreases with a depth of 0.1 cm-1 for snow and only 0.001 cm-1 or less than that for clear ice. Ice is doubly refracting, or weakly birefringent, which ensures the light is absorbed at different rates in different crystallographic directions.
Electromagnetic Properties
The albedo, or reflectivity, of solar radiation, which varies from 0.5 to 0.9 for snow, 0.15 to 0.35 for firn, and 0.3 to 0.65 for glacier ice (a 0 albedo means no reflectivity). Ice and snow are nearly completely “black” (absorbent) at thermal infrared wavelengths, with an albedo of less than 0.01. It means that ice and snow can either radiate or absorb long-wavelength radiation with high efficiency.