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Surface Tension At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to cohesion) than to the molecules in the air (due to adhesion). The net effect is an inward force at its surface that causes the liquid to behave as if its surface were covered with a stretched elastic membrane. Thus, the surface becomes under tension from the imbalanced forces, which is probably where the term "surface tension" came from.[1] Because of the relatively high attraction of water molecules for each other through a web of hydrogen bonds, water has a higher surface tension (72.8 millinewtons per meter at 20 °C) compared to that of most other liquids. Surface tension Surface tension is an important factor in the phenomenon of capillarity. Surface tension Surface tension has the dimension of force per unit length, or of energy per unit area [...More...]  "Surface Tension" on: Wikipedia Yahoo 

Surface Tension (short Story) "Surface Tension" is a science fiction short story by American writer James Blish, originally published in the August 1952 of Galaxy Science Fiction. As collected in Blish's The Seedling Stars, it was revised to incorporate material from his earlier story "Sunken Universe", published in Super Science Stories in 1942.[1]Contents1 Plot summary 2 Reception 3 References 4 External linksPlot summary[edit] A human colonization ship crashlands on a distant planet which is Earthlike but whose only landmass is completely covered in shallow puddles of water and mostly microscopic life forms. Normal humans could not survive on this planet, so the crew must genetically engineer their descendants into something that can survive [...More...]  "Surface Tension (short Story)" on: Wikipedia Yahoo 

International System Of Units The International System of Units International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units (ampere, kelvin, second, metre, kilogram, candela, mole) and a set of twenty decimal prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units. The system also specifies names for 22 derived units for other common physical quantities like lumen, watt, etc. The base units, except for one, are derived from invariant constants of nature, such as the speed of light and the triple point of water, which can be observed and measured with great accuracy [...More...]  "International System Of Units" on: Wikipedia Yahoo 

Damask Damask Damask (/ˈdæməsk/; Arabic: دمشق) is a reversible figured fabric of silk, wool, linen, cotton, or synthetic fibres, with a pattern formed by weaving. Damasks are woven with one warp yarn and one weft yarn, usually with the pattern in warpfaced satin weave and the ground in weftfaced or sateen weave [...More...]  "Damask" on: Wikipedia Yahoo 

Euler–Lagrange Equation In the calculus of variations, the Euler–Lagrange equation, Euler's equation,[1] or Lagrange's equation (although the latter name is ambiguous—see disambiguation page), is a secondorder partial differential equation whose solutions are the functions for which a given functional is stationary. It was developed by Swiss mathematician Leonhard Euler Leonhard Euler and ItalianFrench mathematician JosephLouis Lagrange JosephLouis Lagrange in the 1750s. Because a differentiable functional is stationary at its local maxima and minima, the Euler–Lagrange equation is useful for solving optimization problems in which, given some functional, one seeks the function minimizing or maximizing it [...More...]  "Euler–Lagrange Equation" on: Wikipedia Yahoo 

Hydrophobicity In chemistry, hydrophobicity is the physical property of a molecule (known as a hydrophobe) that is seemingly repelled from a mass of water.[1] (Strictly speaking, there is no repulsive force involved; it is an absence of attraction.) In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents. Because water molecules are polar, hydrophobes do not dissolve well among them. Hydrophobic molecules in water often cluster together, forming micelles. Water Water on hydrophobic surfaces will exhibit a high contact angle. Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove nonpolar substances from polar compounds.[2] Hydrophobic is often used interchangeably with lipophilic, "fatloving" [...More...]  "Hydrophobicity" on: Wikipedia Yahoo 

Hydrophobic Effect The hydrophobic effect is the observed tendency of nonpolar substances to aggregate in aqueous solution and exclude water molecules.[1][2] The word hydrophobic literally means "waterfearing", and it describes the segregation of water and nonpolar substances, which maximizes hydrogen bonding between molecules of water and minimizes the area of contact between water and nonpolar molecules. The hydrophobic effect is responsible for the separation of a mixture of oil and water into its two components [...More...]  "Hydrophobic Effect" on: Wikipedia Yahoo 

Surface Area To Volume Ratio The surfaceareatovolume ratio, also called the surfacetovolume ratio and variously denoted sa/vol or SA:V, is the amount of surface area per unit volume of an object or collection of objects. In chemical reactions involving a solid material, the surface area to volume ratio is an important factor for the reactivity, that is, the rate at which the chemical reaction will proceed. For a given volume, the object with the smallest surface area (and therefore with the smallest SA:V) is the sphere, a consequence of the isoperimetric inequality in 3 dimensions. By contrast, objects with tiny spikes will have very large surface area for a given volume.Contents1 Dimension 2 Physical chemistry 3 Biology 4 Fire spread 5 Mathematical examples 6 See also 7 References 8 External links 9 Further readingDimension[edit] The surfaceareatovolume ratio has physical dimension L−1 (inverse length) and is therefore expressed in units of inverse distance [...More...]  "Surface Area To Volume Ratio" on: Wikipedia Yahoo 

Evaporating Evaporation Evaporation is a type of vaporization, that occurs on the surface of a liquid as it changes into the gaseous phase.[1] The surrounding gas must not be saturated with the evaporating substance. When the molecules of the liquid collide, they transfer energy to each other based on how they collide. When a molecule near the surface absorbs enough energy to overcome the vapor pressure, it will "escape" and enter the surrounding air as a gas.[2] When evaporation occurs, the energy removed from the vaporized liquid will reduce the temperature of the liquid, resulting in evaporative cooling.[3] On average, only a fraction of the molecules in a liquid have enough heat energy to escape from the liquid. The evaporation will continue until an equilibrium is reached when the evaporation of the liquid is the equal to its condensation [...More...]  "Evaporating" on: Wikipedia Yahoo 

Newton (unit) The newton (symbol: N) is the International System of Units International System of Units (SI) derived unit of force. It is named after Isaac Newton Isaac Newton in recognition of his work on classical mechanics, specifically Newton's second law of motion. See below for the conversion factors.Contents1 Definition 2 Examples 3 Commonly seen as kilonewtons 4 Conversion factors 5 See also 6 Notes and referencesDefinition[edit] One newton is the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in direction of the applied force. In 1946, Conférence Générale des Poids et Mesures (CGPM) Resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate 1 kilogram of mass at the rate of 1 metre per second squared [...More...]  "Newton (unit)" on: Wikipedia Yahoo 

Internal Pressure Internal pressure is a measure of how the internal energy of a system changes when it expands or contracts at constant temperature. It has the same dimensions as pressure, the SI unit of which is the pascal. Internal pressure is usually given the symbol π T displaystyle pi _ T [...More...]  "Internal Pressure" on: Wikipedia Yahoo 

Cgs The centimetre–gram–second system of units (abbreviated CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units are unambiguously derived from these three base units, but there are several different ways of extending the CGS system to cover electromagnetism.[1][2] The CGS system has been largely supplanted by the MKS system based on the metre, kilogram, and second, which was in turn extended and replaced by the International System of Units International System of Units (SI) [...More...]  "Cgs" on: Wikipedia Yahoo 

Centimetre Gram Second System Of Units The centimetre–gram–second system of units (abbreviated CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units are unambiguously derived from these three base units, but there are several different ways of extending the CGS system to cover electromagnetism.[1][2][3] The CGS system has been largely supplanted by the MKS system based on the metre, kilogram, and second, which was in turn extended and replaced by the International System of Units International System of Units (SI) [...More...]  "Centimetre Gram Second System Of Units" on: Wikipedia Yahoo 

Erg The erg is a unit of energy and work equal to 10−7 joules. It originated in the centimetre–gram–second (CGS) system of units. It has the symbol erg. The erg is not an SI unit. Its name is derived from ergon (’έργον) a Greek word meaning work or task.[1] An erg is the amount of work done by a force of one dyne exerted for a distance of one centimeter. In the CGS base units, it is equal to one gram centimetersquared per secondsquared (g·cm2/s2). It is thus equal to 10−7 joules or 100 nanojoules (nJ) in SI units [...More...]  "Erg" on: Wikipedia Yahoo 

Radius Of Curvature (mathematics) In differential geometry, the radius of curvature, R, is the reciprocal of the curvature. For a curve, it equals the radius of the circular arc which best approximates the curve at that point [...More...]  "Radius Of Curvature (mathematics)" on: Wikipedia Yahoo 

Standard Conditions For Temperature And Pressure Standard conditions for temperature and pressure are standard sets of conditions for experimental measurements to be established to allow comparisons to be made between different sets of data. The most used standards are those of the International Union of Pure and Applied Chemistry (IUPAC) and the National Institute of Standards and Technology (NIST), although these are not universally accepted standards [...More...]  "Standard Conditions For Temperature And Pressure" on: Wikipedia Yahoo 