Draw a diagram that shows the magnetic fields that result when like poles of two magnets are close to each other when unlike poles are close. Use lines to show the magnetic fields that result from these situations. Warm Up:

Current Can Produce Magnetism Before, you learned Now, you will learn Electric current is the flow of charge Magnetism is a force exerted by magnets Magnets attract or repel other magnets How an electric current can produce a magnetic field How electromagnets are used How motors use electromagnets

Electromagnetism Electromagnetism – magnetism that results from an electric current. When a charged particle moves, it produces a magnetic field. Because an electric current consists of moving electrons, a current in a wire produces a magnetic field. Increasing the amount of current in the wire increases the strength of the magnetic field.

Magnetic Field of a Wire The direction of current Determines the direction Of the magnetic field

Electromagnetism How is a coil of wire that carries a current similar to a bar magnet?

Electromagnet A magnet made by placing a piece of iron or steel inside a coil of wire. As long as the coil carries a current, the metal acts as a magnet and increases the magnetic field of the coil. When the current is turned off, the magnetic domains in the metal become random again and the magnetic field disappears.

Electromagnet By increasing the number of loops in the coil, you can increase the strength of the electromagnet.

Uses of Electromagnets Electromagnets can be turned on and off, and have more uses than permanent magnets. Electromagnets store information on a computer Electromagnets pick up and dumb recycling at a dump Magnetic strips of credit cards Motors

Review 1. Explain how electric current and magnetism are related. 2. Describe three uses of an electromagnet 3. How does an electromagnet differ from a permanent magnet?