Thermal Conductivity
Definition
A material property indicating how well it conducts heat, denoted as k with units W/(m·K). It represents the rate of heat transfer through a unit thickness of material per unit area per degree temperature difference.
Practical Note
Metals have high k (steel ~50, copper ~400 W/(m·K)), while insulators have low k (fiberglass ~0.04, foam ~0.03 W/(m·K)).