It has an invisible magnetic field. Only certain materials, such as iron, feel a magnetic force. Permanent magnets can come in lots of different shapes and sizes. Bar magnets and horseshoe magnets ...

How a Generator Works When an electric current flows through a wire, it generates a three-dimensional magnetic force field around the wire, similar to that surrounding a bar magnet. Magnets are ...

Earth has a magnetic field which appears very similar to a bar magnet that has a north and ... 1990s to about 55 kilometres per year in the direction of Siberia. It is believed that the shifting ...