A magnetic field is invisible, but it can be detected using a magnetic compass. A compass contains a small bar magnet on a pivot so that it can rotate. The compass needle points in the direction ...

what a magnetic field looks like. But as the gelatinous orbs in our skull can perceive only a tiny fraction of the EM spectrum, we have to take those textbook diagrams at face value. That is ...

When an electric current passes through a metal wire, a magnetic field forms around that wire (see diagram at right). Likewise, a wire passing through a magnetic field creates an electric current ...