Invisible Force Fields: Magnetism and Induction

Hold a compass near a wire carrying electricity and watch the needle swing. That should be impossible — the wire is not made of iron, yet it deflects the compass just like a magnet would. In 1820, the scientist Hans Christian Ørsted noticed exactly this by accident during a lecture. It changed physics forever. Before we explain why, think about what you already know: what do you believe a magnet actually does to the space around it?