k-12 outreach

Agenda for a one-hour presentation

What would life be like without magnets?

Everyday we come into contact with many different magnets. Credit cards have a magnetic stripe; audio and

Mr. Magnet showing a young student a magnet.

video tape recorders use magnetic tape; a speaker requires two magnets (a permanent magnet and an electromagnet) to make the sound that we hear; televisions use an electromagnet to "write" the picture on the TV screen; our clothes washers and dryers have electric (magnetic) motors; automobiles use dozens of tiny permanent magnet motors, solenoid magnets and magnetic sensors.

Fundamentals

Anatomy of a magnet

We examine actions of the "magnetic force": push and pull (attraction and repulsion). What are north & south poles? What is the difference between a permanent magnet and an electromagnet? How is the earth like a giant magnet? How does a compass work?

Have you ever seen magnetism?

The "magnetic field" of a magnet can be made visible using iron powder. The magnetism surrounding a wire carrying electrical current can be seen, proving the existence of "electromagetism."

What materials are attracted to a magnet?

Why do magnets stick to your refrigerator? Is your cat magnetic? Wood, plastic, aluminum, copper, brass and steel are tested for magnetic properties. Cheerios are magnetic because they contain iron. What four metals are attracted to a magnet? Magnets always attract iron, nickel, gadolinium and cobalt because these four materials can be "magnetized."

Electricity makes magnetism; the electromagnet

An electromagnet is made from a coil of wire. When electricity is flowing in the wire, magnetism surrounds the coil. You can pick up magnetic materials and release them by shutting off the electricity.

Magnetism makes electricity: the electric generator

Passing a coil of wire through a large magnet causes electricity to flow in the wire. How is electricity generated using magnetism? How much electricity can you crank using the "kid" powered generator?

Electricity and the magnetic force together: the electric motor and a speaker

A motor shaft rotates because of the magnetic force between the "armature" magnet and "field" magnet. A speaker converts electrical current, changing with the beat of the music into sound.

Experiments

The Boomer

A magnetic impulse produces a loud bang and Rice Krispies fly in the air. Sparks appear when a circle of metal foil is cut. A dish is "magneformed." Garfield is launched into space on a magnetic pulse.

A One Million Volt Van der Graaff Electrostatic Generator

The "electric force" attracts or repels all matter. Rice Krispies and Ping-Pong balls fly away from the dome because of the electric force. Why does lightning strike tall objects like trees and tall buildings? Where is the safest place to be during a lightning storm? How does a lightning rod work?

Magnetic Levitation

A 10-inch aluminum pan floats in space on a magnetic field. We tested aluminum and found that it is not magnetic. Then, why does the aluminum feel the magnetic force? Trains in the future may ride on a cushion of magnetism.

For further information about the Mr. Magnet program, please contact Mary Pat McNally, (617) 253-5449.

If you have a question for Mr.Magnet about magnetism, please contact Paul Thomas, (617) 253-8430.

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