Making a Simple Motor

Materials For every student or student team:
1 9 volt battery, 2 small doughnut magnets, 2 paper clips, several inches of insulated wire, sand paper, an object with a 2 cm. diameter for coiling the wire and tape

Instructions:
1) Make a coil of wire by winding insulated wire around a cylindrical object (approx.
c m in diameter). Leave a few inched of wire on either end of the coil. Remove the wire from the object and twist the end of the wire around the coils once or twice to make it stronger.
2) Using sand paper completely remove the insulation from one of the wire ends and from one side of the other end. Place the wire on the table and sand the exposed end.
3)Take 2 paper clips and lift up the outer curve of the clip at a 90 degree angle to the inside curve. Pull the free end of the outside wire so that the curve forms a loop.
4) Take a magnet and tape the unlooped ends of the paper clip to the top, making sure the two paper clips do not touch each other. Place the other magnet on top of the tape.
5) Place the coiled wire in between the two loops of the paper clips, making sure that the non-insulated wire is touching the paper clips.
6) Attach the ends of the two wires to each of the two paper clips and then attach the other ends to either end of the battery.
7) Spin the coil; it should continue to move on its own. if it doesn't try again.

If it still doesn't work:
1) Check to make sure the wies attaching the battery and paper clips are secure and that your battery works.
2) Make sure that only the uninsulated ends of the wire are touching the paper clips.
3) Make sure the paper clips under the top magnet are not touching.
4) Check your coil to make sure it is level. The two ends of the wire need to be straight and level with each other. This is very important to the success of your motor.

Why it Works:
When you hook the coil up to the battery it becomes an electromagnet. When the poles come close to each other they repel. When the electromagnet and the permanent magnet repel each other the coil spins. When the coil spins, the insulated side of one of the wire ends comes into contact with teh paper clip again, the electromagnet field is broken. However, the momentum of the spin continues, when the uninsulated end of the wire comes into contact with teh paper clip again, the pole of the electromagnet is reersed, bringing the coil back towards the magnet.

Inquiry During the Process:
What happens if you add more permanent magnets ot take some away?
What direction does the coil spin? Can you change the direction?
What happens if you use a more/less powerful battery?
What happens if you don't leave one side of the wire end insulated?
Does the number of turns in the coil make a difference?

A version of this lesson was written by Kathryn Mapps and Rachel Jordan and presented to teachers at a Bay Area Science Project and Bay Area Math Project Workshop on 5/11/96