Why Does Aluminum Foil Block Cell Phone Signals? | It Still Works

Why Does Aluminum Foil Block Cell Phone Signals? | It Still Works: A cell phone, wrapped in a layer of aluminum foil, cannot receive calls. The foil, an electrical conductor, creates a barrier called a Faraday Cage around the phone, blocking the radio signals on which it operates. You can easily demonstrate this for yourself by placing a phone on a sheet of aluminum foil, folding the ...