Magnets

Section 1: Magnets and magnetism

1) Any material that attracts iron or materials containing iron is called a magnet. -all magnets have two poles, exert forces, and are surrounded by a magnetic field Demo magnetic field on overhead

2) The parts of a magnet where the magnetic effects are the strongest are called the poles 3The pole of a magnet that points to the north (of Earth) is called the magnet’s north pole –the other pole is the south pole.

4) The force of attraction or repulsion between the poles of magnets is called the magnetic force. Like the law of electric charges, opposites attract, likes repel

5) What makes materials magnetic? Moving electrons produce a magnetic field that gives each atom a north and south pole. In most elements the fields of individual atoms cancel each other out. In iron, nickel and cobalt atoms group together in regions called domains In a domain the atoms line up so that north and south poles create a strong magnetic field.

Un-aligned domains Aligned domains

6) Types of magnets: Temporary- domains may be aligned for a short time Permanent – combinations of Aluminum, Nickel and Cobalt.

7) Magnets from Electricity: Wire wrapped in a coil called a solenoid will generate a magnetic field when current runs through it Strength of the field depends on the size of the current and the number of coils These types of magnets can be turned OFF

8) Electricity is created using magnets through electromagnetic induction. Magnets moved through the coil of wire cause the current of electrons to flow.