Conductivity is the ability of a material to allow the flow of electric current or heat. In electrical terms, materials can be classified as conductors, insulators, or semiconductors based on their conductivity. Metals like copper and aluminum are good conductors, while materials like rubber and glass are poor conductors. In addition to electricity, conductivity also applies to heat transfer. For example, metals typically have high thermal conductivity, meaning they can quickly transfer heat. In contrast, materials like wood and plastic have low thermal conductivity, making them effective insulators in various applications.