This is a really simple magnetic stirrer. All it has is two AA batteries and a 12 V computer fan with a neodymium magnet on top of it. Then a ‘flea’ (a magnetic stirrer bar) goes in the beaker and you put the stirrer underneath and it stirs the mixture. So simple!
You can use any kind of motor, it just shouldn’t spin too fast. A computer fan was the most reliable kind of motor we had available at the time. The magnetic field has to be side on to get the flea to spin (see diagram further down). The magnet was round and had to sit on its edge, so we added a couple of pieces of wood to support it.
We used a retort stand to hold a flask of mixture just above the magnet.
This would have been NZ$160 if we had bought it!!! It was probably under NZ$10 to make!!
This was mixed with the magnetic stirrer and left to form the copper sulphate crystals (CuSO4):
