A simple motor

Here is a motor that you can make in a few minutes.  The motor is as simple as can be.  It's comprised of a battery, a coil of magnet wire and a magnet.  There are a number of variations of this motor online.  Click on the "After School Projects" tab above and go to the section about the motor.  There you will find links that explain how the motor works.

Materials (for each kid)

1 "C" battery

26 AWG magnet wire, 5' [Radio Shack part 278-1345, $6.99]

2 safety pins, size No. 3

1 thick rubber band
1 small neodymium battery

Tools shared by kids in two person teams

1 wire cutters

Step 1:
In step 1, we will make the armature.  The armature is the part of the motor that spins.  It is nothing more than a cylindircal coil of wire.  To make it, wrap it around your C cell battery.  Leave 4 " - 6" unwound  at both ends of the coil.  See the photo below.

Carefully pull the coil off the battery, but pinch it so it doesn't unwind.

To make the coil hold its form permanently, we will tie a knot at each of the free ends of the coil.  The photo below shows the knot before it is pulled tight.

 
Once both knots are tied, make sure they are exactly opposite each other on the coil, as shown in the photo below.

  
The last step in making the armature is incredibly clever and it's what makes the motor turn.  Read all the instructions in this section (Step 1) before you start scraping.  Place the coil on the side of a table, as shown in the photo below.

Use an X-Acto knife (or something similar) to scrape the enamel insulation off the top and sides of the one of the free ends of the wire. You may need to hold the coil on the See the photo below to.  But leave the enamel insulation on the bottom 1/3 of the wire.  Now scrape the top and sides of the nylon insulation of the other free end of the wire.  Here are some tips:

• Make sure you scrape the top of both ends of the wire and that you leave the insulation on the bottom 1/3 of the wire.  You should see BARE COPPER FACING UP ON BOTH WIRE ENDS.
• Be careful to leave the enamel insulation on the bottom of both end.
• You should scrape it well so that you see no enamel insulation left where you are scraping.  You should see shiny copper.
• Make sure you scrape the wire all the way to the knot on the coil.

This is a sketch of what you are trying to do.

The "arms" of the armature (i.e. the part that you just stripped) are going to rest on two safety pins.  The safety pins will be connected to the two ends of the C battery.  Electricity will flow through it when the copper of the armature is facing down because it will be touching the metal of both of the safety pins.  When the copper of the armature's arms is facing up, no electricity will flow because the insulation that you left on the bottom of the wire will be touching the safety pins.

The final step, is to straighten the arms of the armature.  In the photo below, the right arm has been straightened but not the left arm.

Step 2

In step 2, we will make the armature supports.

Take your rubber band and loop it around the battery.  If your rubber band is long, you may have to loop it twice.

Insert each safety pins in at the ends of the C battery as shown in the photo below.  Make sure the end of the safety pin that opens is the one that touches the battery.  Also, make sure they are the same height.

Step 3

In step three, we will finish the motor and troubleshoot any problems.

First, place the armature in the safety pins with the insulation facing down.  (You do this so you don't short circuit the battery.)   Trim the arms of the armatures with your wire clippers (or scissors).  Make sure you leave them long enough that the armature won't fall off the supports if it slides to one end of the battery.  See the photo below.

  

Now, place the magnet on top of the battery in the middle, as shown below.

Lightly tap the armature to start it spinning.  If it doesn't start, spin it in the other direction.  The motor will only spin in one direction.  Sometimes it helps to move the battery a little forward so it's not directly under the armature. 

ONE CAUTION:  NEVER LEAVE THE ARMATURE IN THE BATTERY WHEN IT ISN'T SPINNING.  YOU MAY CAUSE A SHORT CIRCUIT IN YOUR BATTERY AND THE HEAT GENERATED MAY BE ENOUGH TO START A FIRE (OR SO THEY SAY).

If the motor isn't spinning, check the following:

• Make sure you scraped the enamel off the same side of both ends of the armature and that there are no enamel patches on the copper.
• Make sure that you scraped it all the way up to the coils.
• Make sure the arms of the armature are as straight as possible and the armature is level.
• Make sure the arms of the armature are directly opposite each other.