Electrical resistivity and conductivity conductivity in a solution. A rough summary is as follows: This table shows the resistivity (ρ), conductivity and temperature coefficient of various materials at 20 °C (68 °F, 293 K) The effective temperature coefficient varies with temperature and purity level of the material. The 20 °C value is only an approximation when used at other temperatures. For example, the coefficient becomes lower at higher temperatures for copper, and the value 0.00427 is commonly specified at . The extremely low resistivity (high conductivity) of silver is characteristic of metals. George Gamow tidily summed up the nature of the metals' dealings with
Thermal conductivity Thus, the thermal conductivity of nonmetals is approximately constant at high temperatures. At low temperatures well below the Debye temperature, thermal conductivity decreases, as does the heat capacity, due to carrier scattering from defects at very low temperatures. When a material undergoes a phase change from solid to liquid or from liquid to gas the thermal conductivity may change. An example of this would be the change in thermal conductivity that occurs when ice (thermal conductivity of 2.18 W/(m⋅K) at 0 °C) melts to form liquid water (thermal conductivity of 0.56 W/(m⋅K) at 0 °C). Some substances, such as non-cubic