What does thermal conductivity measure in materials?

Thermal conductivity is a property that quantifies how effectively a material can transfer heat through itself. When a temperature difference exists within a material, thermal conductivity determines the rate at which heat energy is conducted from the hotter region to the cooler region.

Materials with high thermal conductivity, such as metals, allow heat to flow easily, making them ideal for applications like heat sinks and cookware. Conversely, materials with low thermal conductivity, such as insulators, impede heat flow and are used in applications where heat retention or prevention is desired, such as in building insulation or thermal barriers.

Understanding thermal conductivity is essential for engineers and designers when selecting materials for thermal management in various applications. This concept is fundamental in fields such as materials science, thermal engineering, and building construction.

The other choices pertain to related but distinct concepts. Resistance to heat refers to thermal resistance, which is the inverse of thermal conductivity and relates to how effectively a material can resist heat flow. The weight of a material falls under its density or specific gravity, and thermal expansion refers to the way materials expand or contract in response to temperature changes, which is another important property but not directly related to thermal conductivity.