Congelation ice
Encyclopedia
Congelation ice is ice
that forms on the bottom of an established ice cover.
, congelation ice is ice that forms on the bottom of an established sea ice
cover, usually in the form of platelets which coalesce to form solid ice.
Only the water freezes to ice, the salt from the seawater is concentrated into brine
, some of which is contained in pockets in the new ice. Due to the brine pockets, congelation ice on seawater is neither as hard nor as transparent as fresh water ice.
, Congelation ice is often called Black Ice. This ice has frozen without many air bubbles trapped inside, making it transparent. Its transparency reveals the colour, usually black, of the water beneath it, hence the name. This is in contrast to snow ice, sometimes called slush ice, which is formed when slush
(water saturated snow) refreezes. Snow ice is white due to the presence of air bubbles.
Black ice grows downward from the bottom of the existing ice surface.
Black ice is very hard, strong and smooth, which makes it ideal for Ice skating
, Skate sailing
, Ice yachting
and some other ice sports.
Thin, clear ice also has acoustic
properties which are useful to tour skaters
. Skating on clear ice radiates a tone whose frequency
depends on the thickness of the ice.
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
that forms on the bottom of an established ice cover.
Seawater
On seawaterSeawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
, congelation ice is ice that forms on the bottom of an established sea ice
Sea ice
Sea ice is largely formed from seawater that freezes. Because the oceans consist of saltwater, this occurs below the freezing point of pure water, at about -1.8 °C ....
cover, usually in the form of platelets which coalesce to form solid ice.
Only the water freezes to ice, the salt from the seawater is concentrated into brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
, some of which is contained in pockets in the new ice. Due to the brine pockets, congelation ice on seawater is neither as hard nor as transparent as fresh water ice.
Fresh water
On the surface of lakes, or other bodies of still, freshwaterFreshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
, Congelation ice is often called Black Ice. This ice has frozen without many air bubbles trapped inside, making it transparent. Its transparency reveals the colour, usually black, of the water beneath it, hence the name. This is in contrast to snow ice, sometimes called slush ice, which is formed when slush
Slush
Slush can mean any of the following:* Slush — a slurry mixture of liquid and solid forms of water.* Slush — a pejorative and slang combination of the likewise derogatory terms slut and lush...
(water saturated snow) refreezes. Snow ice is white due to the presence of air bubbles.
Black ice grows downward from the bottom of the existing ice surface.
Black ice is very hard, strong and smooth, which makes it ideal for Ice skating
Ice skating
Ice skating is moving on ice by using ice skates. It can be done for a variety of reasons, including leisure, traveling, and various sports. Ice skating occurs both on specially prepared indoor and outdoor tracks, as well as on naturally occurring bodies of frozen water, such as lakes and...
, Skate sailing
Skate sailing
Skate sailing is a sport where people on skates are propelled by a sail. Traditionally ice skates are used, but other kinds, such as roller skates can also be used....
, Ice yachting
Ice yachting
Ice yachting is the sport of sailing and racing iceboats, also called ice yachts. It is practiced in Austria, Germany, Great Britain, Poland, Norway and Sweden, to some extent, and is very popular in the Netherlands and on the Gulf of Finland, but its highest development is in the United States and...
and some other ice sports.
Thin, clear ice also has acoustic
Acoustics
Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics...
properties which are useful to tour skaters
Tour skating
Tour skating is a sport and recreational form oflong distance ice skating on natural ice.The Nordic style of tour skating is popular in the Nordic countries,especially Sweden, but increasingly in...
. Skating on clear ice radiates a tone whose frequency
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
depends on the thickness of the ice.