Electrical conductivity is a measure of how well a material can conduct electric current. It depends on the presence of charged particles, such as electrons or ions, that can move freely within the material. Metals, like copper and aluminum, typically have high electrical conductivity, while insulators, such as rubber and glass, have low conductivity. The conductivity of a material can be affected by factors like temperature and impurities. For example, as temperature increases, the conductivity of metals usually decreases due to increased atomic vibrations, which hinder the flow of electrons. In contrast, the conductivity of semiconductors can increase with temperature, making them useful in electronic devices.