For our last session of Winter Makers we built simple, electro-magnetic motors. Since we explored batteries and how they work in our last series with the Lemon Battery Project, it seemed like a great next step for the kids to take.
Our motors were a essentially built from these instructions from Make Magazine (I love those guys!) but with a few small changes. Rather than masking tape, we used electrical tape. I’ve been trying to instill some basic generalities when dealing with electrical things, even if they don’t matter for a particular project. For example, when we made Brush Bots, you don’t really have to connect black to black and red to red, but we did so that they got into the habit. We’ve used electrical tape for our projects in the past, so we went with that this time. Also we used D batteries instead of AA, easier for little hands to wrap the wire around bigger batteries. And finally, instead of trying to bend paperclips, we used large safety pins, when taped to the battery openable side down, the small loops at the top make a great base for the wire to rest in.
per child you will need:
1 battery (D cell)
8 inch piece of electrical tape
2 safety pins
Wrap the wire several times around the battery. It helps to have some three foot lengths pre-cut for the kids. Carefully slip the coil off the battery and wrap the tails around it to hold it together. The tails should extend out about an inch and should be directly across from one another so that they balance well. Sand one tail lightly all the way around, then sand the other tail just on the top side, this creates the on/off that makes the coil spin.
Tape the safety pins to either side of the battery, openable ends down, using the electrical tape. Suspend the coil on the pins by threading the tails through the holes in the safety pins.
Finally, place the magnet on the center of the battery, just under the coil, and give the coil a spin. Test different spots on the battery for the magnet, and different angles for the coil, to see what works best. If it’s all balanced correctly, it should spin for a good while before slowing down.
A word of caution, once assembled, these things can get hot so it’s worth it to tape the battery to the table to help avoid burned finger tips. It’s hard to get the coil of wire perfectly balanced so it doesn’t spin indefinitely, but it will go for a ways and you can see it trying to keep going once it looses steam, which is pretty cool in itself. It’s a great opportunity to explain why the motor works and the force of magnetic fields.
How it went: This was an Ok project. I’ll do it again, but it would be better with maybe a slightly more experienced group. These guys didn’t quite have the hand eye coordination to pull off wrapping the wire, removing it and securing it without help. I had them work in pairs to get this accomplished, but some needed several steps done for them.