A lot of electrical devices such as vacuum cleaners require electricity to operate their motors.
But how exactly does electricity coming out from a static source such as a battery cause another object to move?
Did you know that magnetism is essential in creating a rotating motor?
Here is a very cool experiment to show you how to build a motor using a magnet.
Warning: Magnets are very hazardous if swallowed. Please keep them away from children who still put everything into their mouths.
What you need
- neodymium disc magnet
- (thick) copper wire or this thinner version that we used (which is more challenging but still doable)
- alkaline battery such as AA or AAA
- a plastic ring to support the magnet (optional)
- Cut a piece of copper wire that is roughly 6-8 inches long.
- Bend the wire in the middle to create a contact point to stand on top of the battery.
- While the middle of the wire stands on top of the battery, bend both sides of the wire downwards.
- You can make any shape you want as long as the center can balance on the battery when it spins and the wire frame can touch the magnet that will be placed underneath the battery.
- (Optional) Place the magnet on top of the plastic ring. I use it because my wire frame is quite long and it will touch the table without the ring.
- Carefully put the battery in the center of the disc magnet. Since neodymium magnets are very strong, be careful not to pinch your fingers when doing this. If you need to pull the battery away from the magnet, slide it off the disc. Don’t pull the battery directly from above or you may risk breaking the magnet (or making it very hard to do for yourself).
- Slowly place the wire frame onto the battery and watch it spin.
Warning: Let go of the wire once it makes contact with the battery terminal. Holding a stationary wire to the battery terminals will cause a short circuit which can generate a lot of heat and burn your hand.
Making a wire frame that can balance and spin without falling can require some trial and error.
But once you get the basics, you can try making frames in other shapes.
One especially artsy version of this experiment is this wire dancer.
You just built a motor. Amazing, isn’t it?
What you’ve built is called a homopolar motor, which uses direct current from the battery to power rotational movement.
It is called a homopolar motor because, unlike conventional DC motors, the polarity of the magnetic field from the magnet does not change.
The first ever homopolar motor of this type was built by Michael Faraday in 1821.
Michael Faraday was an English scientist who contributed tremendously to the study of electromagnetism. He was also my very first and only idol in high school.
There, I said it.
When electricity moves through a magnetic field, a force, called Lorentz Force, is generated.
In our experiment, the copper wire conducts electricity from one end of the battery through the magnet to the other end.
As the electric current moves through the magnetic field coming from the neodymium magnet, Lorentz Force is generated which causes the wire to spin.