Observations and results
Were you able to determine which direction magnetic north is? Can you find the other cardinal directions?
If you followed the compass to the north, you would not actually end up at the North Pole because the magnetic poles of the Earth move slowly over time (the current magnetic north is near an island in far northern Canada called Ellef Ringnes Island).
When you ran the needle along the magnet in the same direction, you were making the needle itself magnetic. Many metals contain small clusters of material that are like tiny magnets, but normally these clusters point in different directions, canceling each other out. In that case, the metal object itself does not have an overall magnetic tendency. By running the needle against the magnet in one direction, however, you aligned these small clusters within the needle to face the same direction. You gave the needle itself a single magnetic direction.
Why don't magnets move to align themselves with the magnetic field? Generally the force of gravity and any friction they have on the surface are too strong. But the needle in a compass, such as yours, faces little resistance, so it is free to point in the direction of the magnetic field.
Humans are the only animals that make compasses, but some animals, such as sea turtles, seem to use the Earth's magnetic fields to help them find their way during long migrations. Scientists have found small pieces of magnetite (which is a magnetic substance) in the heads of some animals, which might help them know which way north is. But researchers are still trying to understand exactly how such migration works.
Share your compass observations and results! Leave a comment below or share your photos and feedback on Scientific American's Facebook page.
Cleanup
Carefully remove the needle from the cork. Pour out the water.
More to explore
"The Earth Has More Than One North Pole" from Scientific American
"Magnetic Fields Guide Turtle Hatchlings across the Ocean and Back" from Scientific American
"Magnetism" overview from NASA's Goddard Space Flight Center
"Pigeons Detect Magnetic Fields" from the University of Washington
What Makes a Magnet? by Franklyn M. Branley, ages 4–8
Janice VanCleave's Magnets: Mind-boggling experiments you can turn into science fair projects by Janice VanCleave, ages 9–12
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1 Comments
Add Commentcool article...just one question...the needle seemed to be pointing to the magnet on the table....
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