This conversion equation converts specific heat capacity in units of `"BTU"_"(th)" / ("pound" *""^@"F")` to specific heat capacity specified in units of `J / (kg*""^@"K")`.
Heat capacity (also known as thermal capacity) is the ratio of the heat added to (or subtracted from) an object to the resulting temperature change. The SI unit of heat capacity is joule per kelvin.
Specific heat is the amount of heat needed to raise the temperature of a mass 1 degree Celsius. So, the specific heat capacity is the heat capacity per unit mass of a material.