Electricity flows through a coil of wire when a magnet passes through the coil.
Objective: Students will:
• construct and test a simple motor.
• trace the flow of energy transformations in a system
Understand energy, its transformations, and interactions with matter.
Trace the flow of energy transformations in a system
Demonstration: 5 minutes
Insulated wire, Marker, D Cell battery, Paper clip, Rubber band, Magnet
If you want the students to take their motors home have them bring a D-Cell battery from home.
1. Starting about 3 inches from the end of the wire, wrap it 7 times around the marker pen. Remove the pen. Cut the wire, leaving a 3-inch tail opposite the original starting point. Wrap the two tails around the coil so that the coil is held together and the two tails extend perpendicular to the coil. See illustration below:
Note: Be sure to center the two tails on either side of the coil. Balance is important. You might need to put a drop of glue where the tail meets the coil to prevent slipping.
2. On one tail, use fine sandpaper to completely remove the insulation (bright copper color) from the wire. On the other tail, lay the coil down flat and lightly sand off the insulation from the top half of the wire only.
3. Bend the two paper clips into the following shape (needle-nosed pliers may be useful here):
4. Use the rubber band to hold the loop ends (on the left in the above drawing) to the terminals of the "D" Cell battery:
5. Stick the ceramic magnet on the side of the battery as shown:
6. Place the coil in the cradle formed by the right ends of the paper clips. You may have to give it a gentle push to get it started, but it should begin to spin rapidly. If it doesn't spin, check to make sure that all of the insulation has been removed from the wire ends. If it spins erratically, make sure that the tails on the coil are centered on the sides of the coil. Note that the motor is "in phase" only when it is held horizontally (as shown in the drawing).
7. A picture of the finished motor is shown at the top of this page. A square magnet was used.