Magnetism: Magnetism is the result of spinning or moving charges. Each electron and proton acts like a tiny magnet. In most substances the protons and electrons balance each other in a manner that cancels the atoms overall magnetism. But in some substances like iron there is an imbalance that is not cancelled. In these substances the atoms act like tiny magnets. If a group of these atoms line up with all their north poles in the same orientation the group or domain acts like a larger magnet. If the smaller domains all line up in a bar of iron, for example, then the entire bar behaves as a magnet, with a north pole and a south pole. It is similar to electricity, where unlike poles attract, and like poles repel. It is different from electricity since, separate poles cannot exist by themselves. Magnetism and Electricity are interconnected. Electric fields can influence magnets, and magnetic fields can influence moving charged particles and current carrying wires.

Magnetic Field Direction In Relation to Fixed Magnets: The magnetic field B comes out of a north pole (like E comes out of + charges) and goes into a south pole (like E goes into – charges). It must leave and enter the poles perpendicular to the surface of the magnet. The magnetic field direction is defined as the direction a north needle of a compass points. The north needle points away from north and towards south. So the Earth’s magnetic south pole is located near the Earth’s geographic north pole. B is a measure of magnetic field strength, and is analogous to E for electric fields, and g for gravitational fields.