What does thermal conductivity measure?

Thermal conductivity specifically measures the ability of a material to conduct heat when there is a temperature difference across the material. This property quantifies how efficiently heat energy is transferred through a substance due to a temperature gradient. The higher the thermal conductivity value, the better the material is at transferring heat. This principle is crucial in understanding how materials perform in thermal management applications, such as in building insulation, heat exchangers, and thermal interfaces.

In practical terms, when one side of a material is heated, thermal conductivity explains how quickly and effectively that heat will travel through the material to the cooler side. This concept helps determine suitable materials for various applications in engineering and construction, as materials with high thermal conductivity can easily spread heat, while those with low thermal conductivity can insulate against heat flow, preventing it from escaping or entering a system.