1. 9V Battery
2. Copper wire
3. Neodymium Magnets
4. Plastic Cup
5. LED light
7. Crocodile clips
Experiment Setup - I
Faraday’s electric motor relies on current passing through a liquid. We know the current flows through just fine through a copper wire…but liquid too?
1. Attach some aluminium tape to either sides of a plastic cup.
2. Pour in some water.
3. Connect a LED, switch and a 9V battery to complete the circuit.
4. Complete the circuit and check that the LED glows.
5. Add some salt, and the LED should glow even more brightly.
You can use crocodile clips for better connections.
Experiment Setup - II
Now you are ready to move to the main experiment setup.
1. Use something tall and tape a piece of copper wire horizontally.
2. Bend one into the shape of a hook.
3. Hang another piece of wire from the hook.
4. Place the plastic cup and add some aluminium tape.
5. Place the magnets in the middle.
6. Now fill in the plastic cup with salt water.
7. Complete the circuit.
8. The motor should start working.
Why does the electric motor rotate?
It’s complicated. But a simple explanation is that when current flows through the fire, it creates its own magnetic field. This magnetic field interacts with the magnetic field from the permanent magnets which creates a rotational force on the wire. Switching the circuit off, turns off the magnetic field around the wire, which in turn stops the force on the wire. The wire no longer rotates.
How do the electrons flow in this circuit?
When the circuit is complete, electrons start flowing out of the negative terminal of the battery. They run through the aluminium tape, which is a good conductor of electricity, through the salt water, also a good conductor, up the copper wire that is left to swivel freely, and then finally through the fixed copper wire, and then back into the battery.
Why is a rotating wire useful?
Anything that rotates can be used to do difficult things. For example, here’s a motor connected to a propeller. The propeller rotates round and round and with each rotation it pushes some air back. As a result, the motor, and the car on which the motor is mounted moves forward. Making things move forward using electricity is pretty useful. Beats walking, right?!
Is this setup exactly the same as Faraday’s original attempt?
Close. He used mercury instead of water, since mercury is a far better conductor of electricity than water. But it’s far more poisonous too. So we’re better off using water (with a bit of salt to increase the conductivity) instead.
My motor does not rotate, why?
There could be any number of reasons. First off, check that you have a fresh 9v battery. You need as much of juice flowing the wires as you can get. Try a lighter copper wire. If the wire is too heavy, the force may not be enough to get it to move. Check the circuit.
Adjust the depth to which the wire is submerged. Adjust the number of neodymium magnets. Keep fiddling around, till you get it going. Take notes for when it does not work, and when it does. Any scientific experiment isn’t anything but trial and error.