What does thermal conductivity measure?

Thermal conductivity measures the ability of a material to conduct heat. This property is crucial in determining how quickly heat can pass through a substance when there is a temperature difference. Materials with high thermal conductivity, such as metals, are efficient at transferring heat, which is why they feel hot when touched after being heated. Conversely, materials with low thermal conductivity, such as insulation, do not conduct heat well and are used to reduce heat transfer between environments.

Understanding thermal conductivity is important in various applications, such as building construction, where materials are chosen based on their ability to either conduct or insulate heat, depending on the desired energy efficiency of the structure.