Lesson 3 Summary - Making an Electric Current with Magnets

Magnetism can produce an electric current.  You can do this in one of two ways:

• You can move a magnet near or around a coil of wire.  As long as the magnet keeps moving in some way, you’ll create electricity in the wire.

• You can also move the coil of wire around or near a magnet.  As long as the coil of wire keeps moving, you’ll still create electricity.

You cannot create electricity in a wire by placing a magnet next to the wire and doing nothing.  Either the magnet, the coil of wire, or both must be in motion.

An electric generator is a device that uses a magnetic field to transform mechanical energy into electric energy:

• A coil of wire that can turn is placed between two permanent magnets.

• Mechanical energy turns a shaft or turbine that spins the coil of wire.

• As the coil of wire spins in between the two magnets, electricity is generated in the wire.

Most electric generators produce alternating current (the kind that comes out from an outlet on the wall).  Alternating current is electric current that changes direction in a regular pattern.

A few generators can produce direct current.  Direct current is electricity that flows in only one direction.  Batteries produce direct current.

Power plants use generators to produce large amounts of electricity.  They do this in many ways:

• Wind on a wind farm can be used to turn a fan blade, which turns a coil of wire in a magnetic field.

• Falling water behind a hydroelectric dam can be used to turn a turbine, which turns a coil of wire in a magnetic field.

• Burning coal can be used to boil water, creating a jet of steam that can also be used to turn a turbine, which turns a coil of wire in a magnetic field.