In the physical sciences an intensive property (also called a bulk property) of a system is a physical property of the system that does not depend on the system size or the amount of material in the system. By contrast, an extensive property of a system does depend on the system size or the amount of material in the system. Some intensive properties, such as viscosity, are statistical in nature and not relevant to extremely small quantities. == Headline text ==cant there be some kind of picture somewhere so i can see by picture???? Physical science is a encompassing term for the branches of natural science, and science, that study non-living systems, in contrast to the biological sciences. ... A physical property is any aspect of an object or substance that can be measured or perceived without changing its identity. ... For other uses, see Viscosity (disambiguation). ...

Intensive quantity

An intensive quantity (also intensive variable) is a physical quantity whose value does depend on the amount of the substance for which it is measured. It is the counterpart of an extensive quantity. For instance, the mass of an object is not an intensive quantity, because it depends on the amount of that substance being measured. Density, on the other hand, is a bulk property of the substance. The riddle "what weighs more, a pound of feathers or a pound of lead?" is an example where it is easy to confuse the intensive and extensive quantities. A physical quantity is either a quantity within physics that can be measured (e. ... For other uses, see Density (disambiguation). ... A riddle is a statement or question having a double or veiled meaning, put forth as a puzzle to be solved. ...

Combined intensive quantities

At least two functions are needed to describe any thermodynamic system, an intensive one and an extensive one!

If a set of parameters, {a_i}, are intensive quantities and another set, {A_j}, are extensive quantities, then the function F({a_i},{A_j}) is an intensive quantity if for all α,

It follows, for example, that the ratio of two extensive quantities is an intensive quantity - density (intensive) is equal to mass (extensive) divided by volume (extensive). This article is about the mathematical concept. ...

Joining systems

Let there be a system or piece of substance a of amount m_a and another piece of substance b of amount m_b which can be combined without interaction. [For example, lead and tin combine without interaction, but common salt dissolves in water and the properties of the resulting solution are not a simple combination of the properties of its constituents.] Let V be an intensive variable. The value of variable V corresponding to the first substance is V_a, and the value of V corresponding to the second substance is V_b. If the two pieces a and b are put together, forming a piece of substance "a+b" of amount m_a+b = m_a+m_b, then the value of their intensive variable V is: Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with formula NaCl. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Making a saline water solution by dissolving table salt (NaCl) in water This article is about chemical solutions. ...

which is a weighted mean. Further, if V_a = V_b then V_{a + b} = V_a = V_b, i.e. the intensive variable is independent of the amount. Note that this property holds only as long as other variables on which the intensive variable depends stay constant. In statistics, given a set of data, X = { x1, x2, ..., xn} and corresponding weights, W = { w1, w2, ..., wn} the weighted mean is calculated as Note that if all the weights are equal, the weighted mean is the same as the arithmetic mean. ...

As an example, 60kg of lead, of density 11.34 g·cm−3 and 40kg of tin, of density 6.99 g·cm−3 will combine to form 60 + 40 = 100kg of 60/40 solder of density = 9.60 g·cm−3 General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ... For other uses, see Density (disambiguation). ... This article is about the metallic chemical element. ... A solder is a fusible metal alloy, with a melting point or melting range of 180-190°C (360-370 °F), which is melted to join metallic surfaces, especially in the fields of electronics and plumbing, in a process called soldering. ...

In a thermodynamic system composed of two monatomic ideal gases, a and b, if the two gases are mixed, the final temperature T is Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ... In physics and chemistry, monatomic is a combination of the words mono and atomic, and means single atom. ... An ideal gas or perfect gas is a hypothetical gas consisting of identical particles of zero volume, with no intermolecular forces. ...

a weighted mean where N_i is the number of particles in gas i, and T_i is the corresponding temperature.

Examples

Examples of intensive properties include:

• temperature
• pressure
• chemical potential
• density
• viscosity
• velocity
• electric field
• electrical resistivity
• spectral absorption maxima (in solution)
• specific energy

For other uses, see Temperature (disambiguation). ... This article is about pressure in the physical sciences. ... In thermodynamics and chemistry, chemical potential, symbolized by μ, is a term introduced in 1876 by the American mathematical physicist Willard Gibbs, which he defined as follows: Gibbs noted also that for the purposes of this definition, any chemical element or combination of elements in given proportions may be considered a... For other uses, see Density (disambiguation). ... For other uses, see Viscosity (disambiguation). ... This article is about velocity in physics. ... In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ... // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... Making a saline water solution by dissolving table salt (NaCl) in water This article is about chemical solutions. ... The fuel value or relative energy density is the quantity of potential energy in fuel, food or other substance. ...

Extensive quantity

An extensive quantity (also extensive variable or extensive parameter) is a physical quantity, whose value is proportional to the size of the system it describes. Such a property can be expressed as the sum of the quantities for the separate subsystems that compose the entire system. For other uses, see System (disambiguation). ...

Extensive quantities are the counterparts of intensive quantities, which are intrinsic to a particular subsystem and remain constant regardless of size. Dividing one type of extensive quantity by a different type of extensive quantity will in general give an intensive quantity (mass divided by volume gives density). It has been suggested that this article or section be merged into intensive and extensive properties. ... For other uses, see Mass (disambiguation). ... For other uses, see Volume (disambiguation). ... For other uses, see Density (disambiguation). ...

Combined extensive quantities

If a set of parameters {a_i} are intensive quantities and another set {A_j} are extensive quantities, then the function F({a_i},{A_j}) is an extensive quantity if for all α,

Thus, extensive quantities are homogeneous functions (of degree 1) with respect to {A_j}. It follows from Euler's homogeneous function theorem that In mathematics, a homogeneous function is a function with multiplicative scaling behaviour: if the argument is multiplied by some factor, then the result is multiplied by some power of this factor. ... In mathematics, a homogeneous function is a function with multiplicative scaling behaviour: if the argument is multiplied by some factor, then the result is multiplied by some power of this factor. ...

where the partial derivative is taken with all parameters constant except A_j. The converse is also true - any function which obeys the above relationship will be extensive. In mathematics, a partial derivative of a function of several variables is its derivative with respect to one of those variables with the others held constant (as opposed to the total derivative, in which all variables are allowed to vary). ...

Examples

Examples of extensive properties include:

• mass
• length
• volume
• entropy
• enthalpy
• energy
• electrical resistance
• texture
• heat

For other uses, see Mass (disambiguation). ... For other uses of this word, see Length (disambiguation). ... For other uses, see Volume (disambiguation). ... For other uses, see: information entropy (in information theory) and entropy (disambiguation). ... t In thermodynamics and molecular chemistry, the enthalpy or heat content (denoted as H or ΔH, or rarely as χ) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... In materials science, texture is the distribution of crystallographic orientations of a sample. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ...

Distinction from perceptions

Certain perceptions are often described (or even "measured") as if they are intensive or extensive physical properties, but in fact perceptions are fundamentally different from physical properties. For example, the colour of a solution is not a physical property. A solution of potassium permanganate may appear pink, various shades of purple, or black, depending upon the concentration of the solution and the length of the optical path through it. The colour of a given sample as perceived by an observer (ie, the degree of 'pinkness' or 'purpleness') cannot be measured, only ranked in comparison with other coloured solutions by a panel of observers. Attempts to quantify a perception always involve an observer response, and biological variability is an intrinsic part of the process for many perceived properties. A given volume of permanganate solution of a given concentration has physical properties related to the colour: the optical absorption spectrum is an extensive property, and the positions of the absorption maxima (which are relatively independent of concentration) are intensive properties. A given absorption spectrum, for a certain observer, will always be perceived as the same colour; but there may be several different absorption spectra which are perceived as the same colour: there is no precise one-to-one correspondence between absorption spectrum and colour even for the same observer. In psychology and the cognitive sciences, perception is the process of acquiring, interpreting, selecting, and organizing sensory information. ... You may be looking for an Injective function, in which (f(a)=f(b)) -> a=b, or a Bijection function, which is both injective and surjective (ie. ...

The confusion between perception and physical properties is increased by the existence of numeric scales for many perceived qualities. However, this is not 'measurement' in the same sense as in physics and chemistry. A numerical value for a perception is, directly or indirectly, the expected response of a group of observers when perceiving the specified physical event.

Examples of perceptions related to an intensive physical property:

• Temperature: in this case all observers will agree which is the hotter of two objects.
• Loudness of sound; the related physical property is sound pressure level. Observers may disagree about the relative loudness of sounds with different acoustic spectra.
• Hue of a solution; the related physical property is the position of the spectral absorption maximum (or maxima).

Examples of perceptions related to an extensive physical property: For other uses, see Temperature (disambiguation). ... The horizontal axis shows frequency in Hz Loudness is the quality of a sound that is the primary psychological correlate of physical intensity. ... It has been suggested that this article or section be merged into Sound pressure. ... Acoustics is the branch of physics concerned with the study of sound (mechanical waves in gases, liquids, and solids). ... An image with the hues cyclically shifted The hues in the image of this Painted Bunting are cyclically rotated with time. ...

• Color of a solution: The related physical property is the transmission or absorption spectrum

Color is an important part of the visual arts. ... In most modern usages of the word spectrum, there is a unifying theme of between extremes at either end. ...

See also

• Intrinsic and extrinsic properties

See: Intrinsic and extrinsic properties (philosophy) Intensive and extensive properties (physics) This is a disambiguation page: a list of articles associated with the same title. ...

References

• Callen, Herbert B. (1985). Thermodynamics and an Introduction to Themostatistics, 2nd Ed., New York: John Wiley & Sons. ISBN 0-471-86256-8. 
• Lewis, G.N.; Randall, M. (1961). Thermodynamics, 2nd Edition, New York: McGraw-Hill Book Company.