A permanent magnet is always magnetic. 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 ...

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 reversal could actually have a beneficial effect on Earth. The sun is on the verge of a significant event: a magnetic field reversal. The sun undergoes such a reversal every 11 years ...