In this activity we will look at generating power from spinning the motor.
We know that when we apply a voltage from the battery to the motor then it will spin. This also works the other way: if you spin the motor you will get a voltage on the output. When we are spinning the motor to generate a voltage we call this a 'generator'.
This is how a lot of our electricity is generated: in a wind tubine the wind pushes past and spins the blades which turns a generator which generates electricity. Even in a coal, nuclear or gas electricity power station then the fuel turns water into steam which then turns a turbine which then spins a generator.
In order to test this we need to add the LED to the motor wires. In this example it does not matter which way around the LED is connected, but the LED will only light if the motor is spun in one direction.
Go to a dark place - maybe try this in the evening with lights off and curtains closed? Using two fingers and, with a finger click action, spin the motor spindle. You should see the LED flash brightly for a short time. If not then try spinning in the opposite direction. The LED is 'polarised' which means it has a positive and a negative lead and will only work when the positive lead gets a positive voltage compared to the negative lead.
This only works for a very brief 'flash' of light and the motor needs to be spun very fast to make this work. This might be quite difficult!
So to try and extend the length of time the LED will be powered we are going to try using some string or cotton around the spindle of the motor. I used cotton in this example, but thin string might work better!
You will need some string/cotton and some way of holding the motor firmly to a table. I used cardboard and more sticky tape to hold it to the edge of my table.
This was a still from the video showing the LED lit by spinning the motor.
How else could you use your motor as a generator to power the light?
Links for more resources:
- How to make a Generator at home - YouTube
- How to make a Power Generator - A easy science project DIY - YouTube
- How to Make Electric Generator - YouTube
- Make your own generator (complex!) - Science Project