Editing Shear modulus (section)

==Explanation==
{| class="wikitable" align=right
!Material
!Typical values for <br>shear modulus (GPa)<br> <small>(at room temperature)</small>
|-
|[[Diamond]]<ref name=McSkimin>{{cite journal|last=McSkimin|first=H.J.|author2=Andreatch, P.
 |year = 1972|title=Elastic Moduli of Diamond as a Function of Pressure and Temperature|journal = J. Appl. Phys.|volume = 43|pages=2944–2948|doi=10.1063/1.1661636|issue=7|bibcode = 1972JAP....43.2944M }}</ref>
|478.0
|-
|[[Steel]]<ref name=CDL>{{cite book|author=Crandall, Dahl, Lardner|title=An Introduction to the Mechanics of Solids|publisher=McGraw-Hill|location=Boston|year=1959|isbn=0-07-013441-3}}</ref>
|79.3
|-
|[[Iron]]<ref name=rayne61>{{cite journal|last1=Rayne|first1=J.A.|title=Elastic constants of Iron from 4.2 to 300 ° K|journal=Physical Review|volume=122|pages=1714–1716|year=1961|doi=10.1103/PhysRev.122.1714|issue=6|bibcode =   1961PhRv..122.1714R}}</ref>
|52.5
|-
|[[Copper]]<ref>[http://homepages.which.net/~paul.hills/Materials/MaterialsBody.html Material properties]</ref>
|44.7
|-
|[[Titanium]]<ref name=CDL/>
|41.4
|-
|[[Glass]]<ref name=CDL/>
|26.2
|-
|[[Aluminium]]<ref name=CDL/>
|25.5
|-
|[[Polyethylene]]<ref name=CDL/>
|0.117
|-
|[[Rubber]]<ref name=Spanos>{{cite journal|last=Spanos|first=Pete|year=2003|title=Cure system effect on low temperature dynamic shear modulus of natural rubber
|journal = Rubber World|url=http://www.thefreelibrary.com/Cure+system+effect+on+low+temperature+dynamic+shear+modulus+of...-a0111451108}}</ref>
|0.0006
|-
|[[Granite]]<ref name=Hoek>Hoek, Evert, and Jonathan D. Bray. Rock slope engineering. CRC Press, 1981.</ref><ref name=Pariseau>Pariseau, William G. Design analysis in rock mechanics. CRC Press, 2017.</ref>
|24
|-
|[[Shale]]<ref name=Hoek/><ref name=Pariseau/>
|1.6
|-
|[[Limestone]]<ref name=Hoek/><ref name=Pariseau/>
|24
|-
|[[Chalk]]<ref name=Hoek/><ref name=Pariseau/>
|3.2
|-
|[[Sandstone]]<ref name=Hoek/><ref name=Pariseau/>
|0.4
|-
|[[Wood]]
|4
|}
The shear modulus is one of several quantities for measuring the stiffness of materials. All of them arise in the generalized [[Hooke's law]]:
* [[Young's modulus]] ''E'' describes the material's strain response to uniaxial stress in the direction of this stress (like pulling on the ends of a wire or putting a weight on top of a column, with the wire getting longer and the column losing height),
* the [[Poisson's ratio]] ''ν'' describes the response in the directions orthogonal to this uniaxial stress (the wire getting thinner and the column thicker),
* the [[bulk modulus]] ''K'' describes the material's response to (uniform) [[pressure#Fluid pressure|hydrostatic pressure]] (like the pressure at the bottom of the ocean or a deep swimming pool),
* the '''shear modulus''' ''G'' describes the material's response to shear stress (like cutting it with dull scissors).

These moduli are not independent, and for [[Isotropy#Materials science|isotropic]] materials they are connected via the equations<ref>[Landau LD, Lifshitz EM. ''Theory of Elasticity'', vol. 7. Course of Theoretical Physics. (2nd Ed) Pergamon: Oxford 1970 p13]</ref>
:<math> E = 2G(1+\nu) = 3K(1-2\nu)</math>

The shear modulus is concerned with the deformation of a solid when it experiences a force parallel to one of its surfaces while its opposite face experiences an opposing force (such as friction). In the case of an object shaped like a rectangular prism, it will deform into a [[parallelepiped]]. [[Anisotropic]] materials such as [[wood]], [[paper]] and also essentially all single crystals exhibit differing material response to stress or strain when tested in different directions. In this case, one may need to use the full [[Hooke's law#Tensor expression of Hooke.27s law|tensor-expression]] of the elastic constants, rather than a single scalar value.

One possible definition of a [[fluid]] would be a material with zero shear modulus.