A magnetic stir plate is used to mix a liquid. It's magnet spins around and makes a metal object in the liquid create a vortex to mix it. This project cost me $20-25 but could be more if you don't have some things that I had lying around. Please vote for me!
Step 1: Parts List
You will need:
A computer fan,
A container that fits your computer fan,
2 9-volt batteries,
2 9-volt battery snaps,
Knob that fits the center rod of your potentiometer,
Magnet (I used 3),
Piece of metal like a nail,
Optional: soldering iron and solder.
Step 2: Modify The Container
I used an old Tupperware container, so it had a cover. I put a hole in one of the corners of the lid with a nail for the potentiometer. You want to make sure that it is not above the fan so you can still put the jar over the magnet. Then I cracked one side to feed the wires through.
Step 3: Velcro
For this step you will need 2 circles of each kind of Velcro. First, I put a piece off-center on the bottom of the Tupperware, leaning towards the side without the hole for the potentiometer. I then took off the heatsink that came with the fan and attached the piece of Velcro that sticks to the piece I put down. Then I put another pice on top of the fan. Then the opposing piece goes on the bottom of your magnet.
Step 4: Wiring Part One
Snap on the two battery snaps onto the two batteries, and feed the wires through the whole in the Tupperware. Attach the positive wire from one snap with the negative wire from the other. I just twisted them and then put electrical tape around it, but for a sturdier connection I would solder.