Teacher Pages Grade
four Physical
Sciences Sub Sections: f. Students
know that magnets have two poles (north and south) and that
like poles repel each other while unlike poles attract each
other. Grade
Nine - Twelve: Sub Sections: 5. Electric and magnetic phenomena are
related and have many practical applications.
Teacher
Pages
Electric and Magnetic Phenomena
Electric and Magnetic Phenomena
On this Pathway, you'll see many different kinds of magnets: iron-bar magnets, small grains of black sand that act like tiny magnets, electromagnets that are created by a current of electricity. These magnets are on the Electricity Pathway because electricity and magnetism are very closely related. In fact, all magnetism is the result of moving electric charges-whether they are the charges that flow in an electric current or the tiny electrons spinning around atoms in a piece of iron.
There's something almost magical about a magnet. A magnet creates a magnetic field that pushes and pulls through thin air, acting with a strong invisible power. Though magnetic fields are invisible, you can see their effect on iron filings, compass needles, and other magnets.
If you have any questions or problems, ask an orange-jacketed Explainer for help.
Black Sand
Associated
Snack
Magnetic Lines of Force
Put this sheet of paper on top of the magnet and sprinkle some black sand on it. Move the paper to different parts of the magnet. Is the pattern different in different places? __yes __no
Put your hand on the magnet and sprinkle sand on your hand. Does the magnetic field pass through your hand? __ yes __ no
Visible Magnetic Domains
Look at the orange disk through the microscope
and notice the maze of tiny lines. These lines are tiny magnetized
areas called domains. The dark lines have their north poles facing
up, and the bright lines have their north poles facing
down.
Bring the bar magnet near the disk. The south
pole of the magnet pulls up on the north end of the domains, making
the disk turn dark. What does the other pole of the magnet do to the
disk?
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Magnetic Spinner - watch a video of this exhibit
Magnetic clouds - watch a video of this exhibit.