Here are some great projects for a rainy or snowy winter’s day inside with the family. Getting kids to understand the science behind magnetism and how magnets can be employed to create motors can easily be demonstrated with these simple projects.
The first project, by Instructable member KJMagnetics (a commercial supplier of magnets), shows you how to build a small magnet “car” using little more than a AA battery, a couple of disk magnets, and a sheet of aluminum foil. For the simplest straight-driving car, you use one R841 and two RX032 magnets. Simply by replacing the RX032 magnet on one end with a DC2, you can create a car that races around in a circle.
The Instructable also describes some of the science behind what’s going on:
This setup provides the two main ingredients of an electric motor: A flow of electric current and a strong magnetic field. We get electrical current because there’s an electrical contact between the battery, through the magnets, through the foil, through the magnets on the other end, and back into the battery. […] The magnets are arranged with the same poles facing out. This provides a good magnetic field that’s in a uniform direction across the length of the foil (under the battery). Thus, the current is flowing through a place where there is a strong magnetic field.
In this magnetic “train” tutorial on YouTube, a Japanese maker who goes by the handle AmazingScience builds an awesome electromagnetic train using a coil of bare copper wire and a motor similar to the one used in the magnet car above. He does a really wonderful job of explaining the build and the behavior of the electromagnetism using simple drawings on a sketch pad.
In this video, AmazingScience uses the coil train he built in the first video to create a far more elaborate coil track where the “trains” can run none-stop. It sure looks like a lot of fun (and a lot of work winding such a large coil track). And as KJMagnetics points out, these magnetic cars run at a high current and quickly deplete the batteries that power them to a point where they won’t move anymore. But they sure are cool while they last.