Producing Magnets with Moving CHarge

Magnets have two ends – poles – called north and south. Like poles repel; unlike poles attract.

What happens if you cut a magnet in half? You don’t get One north pole and one south pole, you get two smaller magnets with both poles. No matter how many times you break a magnet, you just get smaller magnets with both poles. Unlike charge, which can have individual positive or negative charges, magnets cannot have lone North or South Poles.

The Earth’s magnetic field is similar to that of a bar magnet. Note that the Earth’s “North Pole” is really a south magnetic pole, as the north ends of magnets are attracted to it. It is believed that the Earth’s magnetic field is produced by the motion of free electrons in the outer core of the Earth.

What makes a magnet? It is not an accident that there seems to be a strong connection between magnetism and electricity. It is believed that moving electric charge produces ALL magnetic fields. If you are hiking during a lightning storm, every time lightning strikes your compass will spin. On ships it was learned through experience that having the compass near current carrying wires caused navigation problems. “I don’t remember the big green statue the last time I sailed to Miami?!?!?”

What makes a magnet? These moving electrons produce magnetic fields, making the atom a “small magnet”. In a substance, groups of the atoms called a domain, form a larger magnet. How these domains line up, determine whether or not the substance is magnetic.

What makes a magnet? In this substance the domains are randomly distributed. This material has little or no magnetic properties. If the domains line up then the material is a magnet. N S Sometimes the domains line up naturally (ferromagnetic). Sometimes you can force the domains to line up by exposing the material to a strong magnetic field. This is not usually permanent.

A solenoid is a long coil of wire. If it is tightly wrapped, the magnetic field in its interior is almost uniform. Placing an iron core inside the loops makes this an electromagnet.