How does aluminum conductivity compare to copper?

Aluminum is known for its lighter weight and lower cost compared to copper, but its electrical conductivity is not as high. Specifically, aluminum has approximately 61% of the conductivity of copper, which can be expressed as 2/3 when comparing their conductivity levels. This means that for every unit of electrical current that copper conducts, aluminum will conduct about 0.67 units. This lower conductivity is significant in applications where weight savings are important, such as in overhead power lines, where aluminum is often favored despite being less conductive. This context is important when considering the materials for electrical applications, as it highlights aluminum's role as a viable alternative to copper under certain circumstances.