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# Try This: Magnetic Electricity by Tom Robinson

## QUESTION

Can electricity confuse a compass?

## MATERIALS

1 piece of insulated wire with bare wire on either end

1 battery (1.5 volts)

## Fun Facts

Some rocks are naturally magnetic. They are called lodestones and were first discovered in a region called Magnesia, near Greece.

## PROCEDURE

• Lay the compass on a table so that it points to the north.

• Place the wire across the top of the compass so that it lies in the same direction that the compass points. Leave the exposed ends of the wire outside the compass.

• Touch each end of the wire to opposite ends of the battery. Observe what happens to the compass.

## Fun Facts

The magnetic north pole (the location a compass points to) isn't located at the true North Pole. It's actually located at Ellef Ringnes Island in the Canadian arctic. It moves to the northwest approximately 15 kilometers each year.

## WHAT'S HAPPENING

Hans Christian Oersted discovered that electricity flowing through a wire, called a current, makes the wire act like a magnet. The magnet formed by the electricity attracts the compass, which is a very small magnet itself, and makes it point in a direction different from north.

## FOLLOW-UP

Remove the wires from the battery and watch the compass return to its normal position. Now place the wire under the compass and touch the wires to the battery again. What do you see5?

What did one magnet say to the other magnet?

“I find you very attractive.”

KIDS' LAB LESSONS

QUESTION How does an electromagnet work?

EXPERIMENT OVERVIEW In this experiment you will build your own electromagnet. By wrapping wire around a screwdriver, you will strengthen the magnetic field produced by the current flowing in the wire (which you explored in the previous experiment). Then you'll be able to measure the strength of your electromagnet by counting the number of paper clips you can hold.

SCIENCE CONCEPT Since one wire is known to produce a magnetic field, wrapping a wire into a series of loops or coils strengthens that effect. These coils are called solenoids; when they are used with a metallic core (like a screwdriver), they produce surprisingly strong magnetic fields. When an ordinary nail is exposed to those fields, it, too, becomes magnetized, as long as the field is there.

MATERIALS

Long piece of copper wire, preferably insulated

Screwdriver

Tape AA, C, or D battery

Paper clips

electromagnet: a magnet made by passing electrical current through a wire.

solenoid: a cylinder of wire formed into coils.

## Fun Facts

Electromagnets differ from permanent magnets in that they can be turned on and off.

PROCEDURE

• Leaving about 3 inches of one end of the wire free, wrap the wire around the screwdriver 10 times.

• Tape one end of the wire to the negative terminal (marked with a “ — ”) of the battery.

• Hold the handle of the screwdriver in one hand while you touch the free end of the wire to the positive terminal (marked with a “+”) of the battery.

• See how many paper clips you can pick up and hold with the screwdriver.

• Remove the free wire from the battery and wind another 10 loops around the screwdriver.

• Repeat the experiment and count the number of paper clips you can pick up.

• Again, remove the free wire from the battery.

• Wind any remaining wire around the screwdriver, leaving about 3 inches of wire free and repeat the experiment.

QUESTIONS FOR THE SCIENTIST

• What made the screwdriver turn into a magnet?___________________________________

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• How did you turn the electromagnet on and off?________________________

• What effect did adding more coils to the screwdriver have on the number of paper clips you could pick up?______________________________________________

• What advantages might there be to using a magnet that can be turned on and off?_____________________________________________________________________

FOLLOW-UP Practice lifting paper clips, moving them through the air, and then dropping them in another location. Can you think of anywhere someone would want to do this?6___________________________________________________

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