Bar magnets and horseshoe magnets are two of the most common shapes of magnet. The magnetic field is shown by lines with arrows that point from north to south. You can tell how old some coins are ...

How a Generator Works When an electric current flows through a wire, it generates a three-dimensional magnetic force field ... over the magnet. The filings align themselves along the lines of ...

the angle at which magnetic field lines intersect the Earth. The turtles use these two pieces of information, which vary at every point on the planet's surface, as navigational markers that help ...