How to Teach With Magnets
Fun magnet experiments demonstrate basic principles that apply to physics, geology, engineering and other scientific disciplines. All magnets have north and south poles. Similar poles repel, while opposite poles attract. Magnetic strength varies due to atom alignment and electron movement. A magnetic field has lines of force. Closer field lines represent a stronger magnet. One field line per centimeter equals one Gauss. Magnetic force passes through some obstacles. A magnet moving through an electrical conductor generates eddy currents and a magnetic field, which repels the magnet.
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Things You'll Need
- Bar magnets
- Compass
- Magnets, differing shapes and strengths
- Paper clips
- Plastic box
- 1 tsp. iron filings
- Plastic sheet
- Tape
- Wood sheet
- Styrofoam tray
- Aluminum foil
- Metal cookie sheet
- Thick fabric
- 3 feet of aluminum tubing
- Pencil
- Neodymium magnet
- 3 feet of plastic tubing
Instructions
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1
Place two magnets together and determine whether they attract or repel. Turn one magnet and repeat. Position a compass nearby and find the north and south poles of each magnet.
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2
Test the strength of four different magnets. Have students predict which magnet will be strongest or weakest. Reach one magnet into a plastic box of paperclips. Count the number of paperclips attached to the magnet. Repeat with remaining three magnets and rank the relative strength of the magnets by the number of attached paperclips.
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3
Pour iron filings into a plastic box. Tape a plastic sheet onto the top and seal all edges. Place a magnet underneath and tap the box gently. Filings will position along magnetic field lines. Count the number of field lines in a square centimeter. Repeat with a different magnet. Compare magnet strengths to those from step 2.
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4
Put a strong magnet about 2 inches from the compass. Note any compass needle movement. Ask students to predict whether any experimental materials will affect the magnetic field. Place wood in between and record compass needle position. Repeat with Styrofoam, aluminum foil, a cookie sheet, fabric, and a student's hand. List the materials that shielded the magnetic field.
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5
Hold an aluminum tube upright and drop pencil down. Then drop neodymium magnet down the tube. Drop pencil and magnet through plastic tubing. Ask students why the magnet falls more slowly in the aluminum tubing.
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Tips & Warnings
Use a wand magnet, magnetic marble, paint, and paper to create art. Extend the experiments to make science fair projects.
Keep magnets away from computers, video and audio tapes, speakers, and other electronic devices. Use care with strong magnets; wear safety goggles and bring them together slowly to prevent chipping or injury. Keep strong magnets away from small children to avoid injury or ingestion.
