As suggested at Boing Boing here, we made a simple motor.
We used an AA battery, two large safety pins, sticky tape, 30 cm wire, nail polish, and a magnet. Plus some post-it notes and lego to get the magnet to the right height.
You tape the safety pins to either end of the battery so that the loop of each safety pin is at the top. Then you make a wire coil to fit between the safety pins. The ends of the coil have any insulation stripped off and are painted with nail polish along the top surface only. Once that dries, you put the wire coil between the pins and adjust the magnet to be at the right height so that the wire coil will spin.
A couple of points worth noting:
- For making the coil we found that solid conductor wire works better than stranded wire. It is stiffer and also easier to get the nail polish along one surface. (It has a single strand of wire within the insulation instead of several – see photos below.)
- We used the magnet from an old computer hard drive – these are quite strong and are well worth extracting if you get the chance.
- If you leave the wire sitting in place for very long but *not* turning, you will short out your battery and melt it …
The result was quite pleasing: