What should students know
            about magnetism?


    Magnetism is nothing mysterious.
      Here is some of what we know:


---   Magnetism of iron ("permanent magnetism") makes possible the magnetic compass and lets drawings be stuck to refrigerator doors. But it's just an accident of nature.

---   The true nature of the magnetic force is the attraction or repulsion between electric currents. That was discovered by Oersted and by Ampére in 1820.

---   The Earth is magnetic because electric currents flow in it (and the same with sunspots). There is no magnet inside it (it has a lot of iron, but it's too hot).

---   Electric and magnetic phenomena are closely linked. That link not only makes electric machinery possible, but also radio, microwaves, light and x-rays, all of which are "electromagnetic waves".

---   Magnetic fields have no effect on your living tissue. Magnets don't do a thing for your health (or for your car's gas mileage).