Here's why:

* Metals have free electrons: The atoms in metals have loosely bound electrons that can easily move throughout the material. These free electrons are what carry electrical current.

* Conductors allow current flow: When a voltage is applied across a metal hanger, these free electrons flow through the material, creating an electrical current.

In contrast, insulators have tightly bound electrons that cannot move freely, preventing the flow of electricity. Examples of insulators include rubber, plastic, and wood.