Most kids probably know the North Pole as home to good old Santa Claus and his elves and reindeer. Older and/or smarter kids may also know that it’s one of Earth’s magnetic poles, along with, obviously, the South Pole. But what does “magnetic pole” really mean, and how can one visually demonstrate the effect of our planet’s magnetic forces?
Why, with this simple Demo Science science demonstration, that’s how!
For this experiment, the following supplies are required: a bar magnet, preferably at least six inches long; a length of string—depending on your available space and how high up a ladder you want to climb, this string should be between six and 300 feet long; a ladder; tape; a writing utensil; and a structure from which you can safely hang your magnet.
First, tie one end of the string around the center of your bar magnet. Write an “N” and an “S”, respectively, on two small pieces of tape, and affix said tape to the magnet to properly identify its North and South ends. Set up your ladder, have the least easily-distracted kid in class hold it steady for you, and clamber up to tie the other end of your string around a light fixture, basketball hoop, rafter, fully-extended forklift arm, or other overhead structure. Be sure to leave enough ground clearance for the magnet to hang and swing freely—try to keep it about waist-high.
Adjust the hanging magnet, as needed, to ensure it balance properly and doesn’t hang down (too much) on one end. Then, spin the magnet a few times as it hangs free so that it rotates on its own a few times. Have your students observe what happens, repeating the spin/rotate process if desired.
Observation of Experimentation
So, what happened? If everything works out right (and it almost invariably should, barring some huge flub on your part), the magnet will, at the end of its rotations, align itself in the same direction as it began. No matter how many times it spins whilst hanging there, the magnet’s poles will end up pointing North and South, just as your N and S indicate. Because it’s hanging freely, it will act as a compass and align itself to the earth’s magnetic field. It’s magnet magic science!