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Supercooling
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid. Per the established international definition, supercooling means ''‘cooling a substance below the normal freezing point without solidification’.'' IIR International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.php ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology While it can be achieved by different physical means, the postponed solidification is most often due to the absence of nucleation, seed crystals or nuclei around which a crystal structure can form. The supercooling of water can be achieved without any special techniques other than chemical demineralization, down to . Supercooled water can occur naturally, for example in the atmosphere, animals or plants. This phenomenon was first identified in 1724 by Daniel Gabriel Fahrenheit, while developing Fahren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freezing Point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilibrium, equilibrium. The melting point of a substance depends on pressure and is usually specified at a Standard temperature and pressure, standard pressure such as 1 Atmosphere (unit), atmosphere or 100 Pascal (unit), kPa. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of substances to Supercooling, supercool, the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact, the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the #Melting point measurements, melting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superheating
In thermodynamics, superheating (sometimes referred to as boiling retardation, or boiling delay) is the phenomenon in which a liquid is heated to a temperature higher than its boiling point, without boiling. This is a so-called ''metastable state'' or '' metastate'', where boiling might occur at any time, induced by external or internal effects.Debenedetti, P.G.Metastable Liquids: Concepts and Principles; Princeton University Press: Princeton, NJ, USA, 1996.Maris, H., Balibar, S. (2000"Negative Pressures and Cavitation in Liquid Helium"Physics Today 53, 29 Superheating is achieved by heating a homogeneous substance in a clean container, free of nucleation sites, while taking care not to disturb the liquid. This may occur by microwaving water in a very smooth container. Disturbing the water may cause an unsafe eruption of hot water and result in burns. Cause Water is said to "boil" when bubbles of water vapor grow without bound, bursting at the surface. For a vapor bubble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freezing Rain
Freezing rain is rain maintained at temperatures below melting point, freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike rain and snow mixed, a mixture of rain and snow or ice pellets, freezing rain is made entirely of liquid droplets. The raindrops become supercooling, supercooled while passing through a sub-freezing layer of air hundreds of meters above the ground, and then freeze upon impact with any surface they encounter, including the ground, trees, electrical wires, aircraft, and automobiles. The resulting ice, called glaze (ice), glaze ice, can accumulate to a thickness of several centimeters and cover all exposed surfaces. The METAR code for freezing rain is FZRA. A storm that produces a significant thickness of glaze ice from freezing rain is often referred to as an ice storm. Although these storms are not particularly violent, freezing rain is notorious for causing travel problems on roadways, breaking tree limbs, and downing power l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystalization
Crystallization is a process that leads to solids with highly organized atoms or molecules, i.e. a crystal. The ordered nature of a crystalline solid can be contrasted with amorphous solids in which atoms or molecules lack regular organization. Crystallization can occur by various routes including precipitation from solution, freezing of a liquid, or deposition from a gas. Attributes of the resulting crystal can depend largely on factors such as temperature, air pressure, cooling rate, or solute concentration. Crystallization occurs in two major steps. The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent. The second step is known as crystal growth, which is the increase in the size of particles and leads to a crystal state. An important feature of this step is that loose particles form layers at the crystal's surface and lodge themselves into open inconsistencies such as pores, cracks, etc. Crystallizatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solute
In chemistry, a solution is defined by IUPAC as "A liquid or solid phase containing more than one substance, when for convenience one (or more) substance, which is called the solvent, is treated differently from the other substances, which are called solutes. When, as is often but not necessarily the case, the sum of the mole fractions of solutes is small compared with unity, the solution is called a dilute solution. A superscript attached to the ∞ symbol for a property of a solution denotes the property in the limit of infinite dilution." One important parameter of a solution is the concentration, which is a measure of the amount of solute in a given amount of solution or solvent. The term "aqueous solution" is used when one of the solvents is water. Types ''Homogeneous'' means that the components of the mixture form a single phase. ''Heterogeneous'' means that the components of the mixture are of different phase. The properties of the mixture (such as concentration, tempe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freezing-point Depression
Freezing-point depression is a drop in the maximum temperature at which a substance freezing, freezes, caused when a smaller amount of another, non-Volatility (chemistry), volatile substance is added. Examples include adding salt into water (used in ice cream makers and for De-icing#Chemical de-icers, de-icing roads), Alcohol (chemistry), alcohol in water, Ethylene glycol, ethylene or propylene glycol in water (used in antifreeze in cars), adding copper to molten silver (used to make Solder#Hard_solder, solder that flows at a lower temperature than the silver pieces being joined), or the mixing of two solids such as impurities into a finely powdered drug. In all cases, the substance added/present in smaller amounts is considered the solute, while the original substance present in larger quantity is thought of as the solvent. The resulting liquid solution or solid-solid mixture has a lower Melting point, freezing point than the pure solvent or solid because the chemical potentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiling Point
The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum, i.e., under a lower pressure, has a lower boiling point than when that liquid is at atmospheric pressure. Because of this, water boils at 100°C (or with scientific precision: ) under standard pressure at sea level, but at at altitude. For a given pressure, different liquids will boiling, boil at different temperatures. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, one Atmosphere (unit), atmosphere. At that temperature, the vapor pressure of the liquid becomes sufficient to overcome atmospheric pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amorphous Ice
Variations in pressure and temperature give rise to different phases of ice, which have varying properties and molecular geometries. Currently, twenty-one phases, including both crystalline and amorphous ices have been observed. In modern history, phases have been discovered through scientific research with various techniques including pressurization, force application, nucleation agents, and others. On Earth, most ice is found in the hexagonal Ice Ih phase. Less common phases may be found in the atmosphere and underground due to more extreme pressures and temperatures. Some phases are manufactured by humans for nano scale uses due to their properties. In space, amorphous ice is the most common form as confirmed by observation. Thus, it is theorized to be the most common phase in the universe. Various other phases could be found naturally in astronomical objects. Theory Most liquids under increased pressure freeze at ''higher'' temperatures because the pressure helps to hold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Journal Of Experimental Biology
''Journal of Experimental Biology'' (formerly ''The British Journal of Experimental Biology)'' is a peer-reviewed scientific journal in the field of comparative physiology and integrative biology. It is published by The Company of Biologists. The journal is partnered with Publons and has two-way integration with bioRxiv. ''Journal of Experimental Biology'' is now a hybrid journal and publishes 24 issues a year. Content over six months old is free to read. History ''The'' ''British Journal of Experimental Biology'' was established in Edinburgh in 1923 (''Br. J. Exp. Biol.'': ). It was published by Oliver and Boyd and edited by F. A. E. Crew with an Editorial Board of nine members, including Julian Huxley. When the journal ran into financial trouble, George Parker Bidder II, the founder of The Company of Biologists, rescued it in 1925. Sir James Gray was appointed as the journal's first Editor-in-Chief in 1925 and the journal was renamed ''The Journal of Experimental Biol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
