Thermal conductivity is a measure of a material's ability to conduct heat. It indicates how quickly heat can pass through a substance when there is a temperature difference. Materials with high thermal conductivity, like metals, transfer heat efficiently, while those with low thermal conductivity, such as wood or rubber, act as insulators. This property is important in various applications, including building construction and electronics. For example, in insulation materials, low thermal conductivity helps keep buildings warm in winter and cool in summer. In electronic devices, managing thermal conductivity is crucial to prevent overheating and ensure optimal performance.