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Skills Focus: observing
An electric motor converts electricity into motion. Can you use a small motor to create an optical illusion that will mesmerize your partner?
Obtain a motor from your teacher. Cut a circle out of thin cardboard and attach it to the shaft of the motor. Draw a pinwheel pattern on a white piece of paper and tape it to be cardboard base. Connect the motor to a battery and a switch using connecting wires ( Figure 1 ). Observe what happens when you close the circuit.
Figure 1
1.
Have your partner look at the pinwheel pattern while the circuit is closed. What does your partner see?
2.
Switch places with your partner. Describe what you see when you look at the pinwheel pattern when the circuit is closed.
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LEARNING TIP
The words “motor” and
“motion” both come from the Latin word meaning
“move.”
Unit B Electricity
If you looked around your home, you would find many electric motors. You would find them in small appliances, such as a blender, a hair dryer, and the disk drives in a computer or CD player. You would also find motors in large appliances, such as a refrigerator
( Figure 2 ), a dishwasher, and a washing machine. There are also electric motors in most electric tools, such as drills, saws, sanders, and planers. The windshield wipers on your family car are powered by an electric motor, as is an entire electric trolley bus ( Figure 3 ).
If something electric has a part that moves, it probably has a motor.
NEL

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Figure 2
The electric motor of your refrigerator powers a compressor to keep your food cold.
Figure 3
An electric trolley bus gets its power from overhead electrical cables.
A motor transforms electricity into motion. Although a motor uses electricity, it actually works using electromagnetism. Inside a motor is a permanent magnet and an electromagnet, which can rotate. When the circuit is closed, the electromagnet is constantly repelled and attracted to the permanent magnet. This causes the electromagnet to turn. This also causes anything that is attached to the electromagnet to turn, causing motion. When the circuit is open, the motor stops working because the coil is no longer an electromagnet.
1.
How is electricity transformed into motion?
2.
What appliances in your home transform electricity into motion?
NEL
7.4
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