※ 引述《Andretti (Rookie)》之銘言： : 大家好! : 請問固體(Soild),小至碳酸鈉粉末之類的, : 可以檢測固體的黏度(Viscosity)單位[cP]嗎? : 還是只有流體有黏度,固體沒有黏度呢? : 問題: : 1.固體有沒有黏度呢? : 2.一般來說(95%以上的狀況而言), : 固體(Solid)是無法測黏度而且黏度係數(cP)也無法知道是多少嗎? : 3.理論上來說(5以下的狀況而言), : 固體(Solid)是可以測黏度而且可以黏度係數(cP)也知道是黏度多少嗎? : 謝謝大家! 我再wiki上看到，但其實wiki的東西也不能完全儘信啦 Can solids have a viscosity? If on the basis that all solids flow to a small extent in response to shear stress then yes, substances know as Amorphous solids, such as glass, may be considered to have viscosity. This has led some to the view that solids are simply liquids with a very high viscosity, typically greater than 1012 Pa‧s. This position is often adopted by supporters of the widely held misconception that glass flow can be observed in old buildings. This distortion is more likely the result of glass making process rather than the viscosity of glass. However, others argue that solids are, in general, elastic for small stresses while fluids are not. Even if solids flow at higher stresses, they are characterized by their low-stress behavior. Viscosity may be an appropriate characteristic for solids in a plastic regime. The situation becomes somewhat confused as the term viscosity is sometimes used for solid materials, for example Maxwell materials, to describe the relationship between stress and the rate of change of strain, rather than rate of shear. These distinctions may be largely resolved by considering the constitutive equations of the material in question, which take into account both its viscous and elastic behaviors. Materials for which both their viscosity and their elasticity are important in a particular range of deformation and deformation rate are called viscoelastic. In geology, earth materials that exhibit viscous deformation at least three times greater than their elastic deformation are sometimes called rheids. One example of solids flowing which has been observed since 1930 is the Pitch drop experiment 作者以glass為例也指出may be considered to have viscosity 有些物質隨溫度昇高時，固液兩態並沒有明顯界限。對於這種情況，作者用dynamical viscosity 大於多少來界定，上面的例子指出dynamical viscosity大於10^12次方Pa．s時，定為固態。 所以我覺得固體也是有cp的。 --

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