The Simplest Motor

This experiment can be a great, easy way to learn how motors work. This motor uses a permanent magnet, some wire, paperclips, and some batteries.

Permanent magnets are used in many electric motors and generators. This simple motor includes all of the relevant parts and ideas that you'll find in most electric motors.

What you'll need:

-Strong, permanent magnet. We of course used a strong neodymium magnet that is 3/4" in diameter, 1/4" thick (our magnet DC4).

-Paperclips

-Magnet wire (we found 24 gauge wire worked well)

-One or more AA batteries

-A base of some kind (wood, Styrofoam, legos, etc)

First, we'll take a length of 24 gauge magnet wire and construct the rotor.

Take several feet of this wire and construct a loop, as shown in the picture. To keep the size of the coil constant, wrap the wire around a thick pen, marker, or other cylindrical object. Anywhere from 10 to 35 turns seems to work well, but experiment with different amounts!

We wound ours around a AA battery, which was a nice size.

Leave the two ends of the wire sticking out from either side of the coil. You can tape or wrap something around the coil in a few places to keep it together.

The rotor is a simple length of wire, wound in a coil, with two ends of the wire sticking out at either end. On one side, remove all of the insulation on the wire sticking out from the coil. You can do this by lightly scraping it with a knife, all the way around a wire. (PLEASE SEEK ADULT SUPERVISION FOR THIS).

Here's a very important part: On the other side of the coil, only remove half of the insulation as shown in the picture. This part is critical to control the flow of electricity, switching it on and off as the wire rotates. Only scrape a small strip off.

Using two paperclips, construct a holder that will hold the rotor. The distance between the paperclips should be shorter than the ends sticking out from the rotor. We set ours in a piece of Styrofoam to hold them in place.

Connect the ends of your battery (or batteries) to the two paperclips. One paperclip is connected to the negative side of the battery, one paperclip to the positive side of the battery. We used alligator clips and an old battery holder from an RC car.

Set the strong magnet beneath the rotor. The best position might vary, depending on the angle between the rotor's coil and where exactly you scraped the insulation off. We secured the magnet down with a piece of scotch tape.

The last step is to set your rotor onto the stator and watch it spin!

For some great technical information about how this works, check out our recent blog article here!

Pose your own scientific hypothesis and do a bit of testing to see what really happens!

Some example questions...

1. How does the number of turns of wire affect performance?
2. How does the size and position of the base magnet affect performance?
3. Can performance be improved by using two magnets, one above and below the coil?
4. How does varying the voltage affect performance?
5. Does using a different magnet wire gauge change anything?
6. How does the size of the coil affect performance?

Let us know what you come up with!