Thermal conductivity is a measure of how well a material can conduct heat. It indicates how quickly heat can pass through a substance when there is a temperature difference. For example, metals like copper and aluminum have high thermal conductivity, meaning they transfer heat efficiently, making them ideal for cooking utensils and heat exchangers. In contrast, materials like wood and styrofoam have low thermal conductivity, which means they are good insulators. These materials help keep heat in or out, making them useful for building homes and keeping food warm or cold. Understanding thermal conductivity is essential in various fields, including engineering and construction.