Here's why:

* Metals are good conductors because they have free electrons that can easily move throughout the material.

* Aluminum is a highly conductive metal, which is why it's used in electrical wiring and other applications where conductivity is important.

However, a pop can's protective coating (the inside and outside layers) can be made of materials that are more insulating, like lacquer. While the aluminum itself conducts, the coating can slow down or prevent the flow of electricity.

Therefore, a pop can is primarily a conductor, but its protective coating can make it act as an insulator in certain situations.