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Sigma-t
Sigma-t is a quantity used in oceanography to measure the density of seawater at a given temperature. σT is defined as ρ(S,T)-1000 kg m−3, where ρ(S,T) is the density of a sample of seawater at temperature T and salinity S, measured in Kilogram per cubic metre, kg m−3, at standard atmospheric pressure. For example, a water sample with a density of 1.027 g/cm3 has a σT value of 27. References {{reflist, 28em See also *Water (molecule)#Density of saltwater and ice, Density of saltwater and ice Units of density ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanography
Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate tectonics and the geology of the sea floor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers utilize to glean further knowledge of the world ocean, including astronomy, biology, chemistry, climatology, geography, geology, hydrology, meteorology and physics. Paleoceanography studies the history of the oceans in the geologic past. An oceanographer is a person who studies many matters concerned with oceans, including marine geology, physics, chemistry and biology. History Early history Humans first acquired knowledge of the waves and currents of the seas and oceans in pre-historic times. Observation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematically, density is defined as mass divided by volume: : \rho = \frac where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight. For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium and iridium are the densest known elements at standard conditions for temperature and pressure. To simplify comparisons of density across different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilogram Per Cubic Metre
The kilogram per cubic metre (symbol: kg·m−3, or kg/m3) is the unit of density in the International System of Units (SI), defined by mass in kilograms divided by volume in cubic metres. Conversions *1 kg/m3 = 1 g/ L (exactly) *1 kg/m3 = 0.001 g/cm3 (exactly) *1 kg/m3 ≈ 0.06243 lb/ ft3 (approximately) *1 kg/m3 ≈ 0.1335 oz/US gal (approximately) *1 kg/m3 ≈ 0.1604 oz/ imp gal (approximately) *1 g/cm3 = 1000 kg/m3 (exactly) *1 lb/ft3 ≈ 16.02 kg/m3 (approximately) *1 oz/(US gal) ≈ 7.489 kg/m3 (approximately) *1 oz/(imp gal) ≈ 6.236 kg/m3 (approximately) Relation to other measures The density of water is about 1000 kg/m3 or 1 g/cm3, because the size of the gram was originally based on the mass of a cubic centimetre of water. In chemistry, g/cm3 is more commonly used. See also * Gram per cubic centimetre The gram per cubic centimetre is a unit of density in the CGS system, commonly used in chemistry, defined as mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water (molecule)
Water () is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" and the "solvent of life". It is the most abundant substance on the surface of Earth and the only common substance to exist as a solid, liquid, and gas on Earth's surface. It is also the third most abundant molecule in the universe (behind molecular hydrogen and carbon monoxide). Water molecules form hydrogen bonds with each other and are strongly polar. This polarity allows it to dissociate ions in salts and bond to other polar substances such as alcohols and acids, thus dissolving them. Its hydrogen bonding causes its many unique properties, such as having a solid form less dense than its liquid form, a relatively high boiling point of 100 °C for its molar mass, and a high heat capacity. Water is amphoteric, mean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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