Main Page | See live article | Alphabetical index In heat transfer analysis, thermal diffusivity is the ratio of thermal conductivity to heat capacity. where k is thermal conductivity and ρcp is heat capacity. Units are mē/s. Substances with high α will rapidly adjust their temperature to that of surroundings, because they conduct heat quickly in comparison to their thermal 'bulk'. See also thermodynamics. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.