Some animals also navigate using the earth’s magnetic field. From the idea that there may be some relationship with these two things, this experimental earthquake detector was born. [ ...

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 ...

The needle is being affected by the Earth’s magnetic field. One end points towards magnetic north and the other end points south. You can use a compass to check which direction each end is facing.

How a tokamak works: The electric field induced by a transformer drives a current (big red arrows) through the plasma column. This generates a poloidal magnetic field that bends the plasma current ...