This instructable shows us how to make a magnetic stirrer, that can be used in your home lab, from the following items:
An old 3" PC fan
A dead hardrive
A 12v ac adaptor
Misc Items depending on your taste for getting things done :)
Read on, and enjoy.
Not my original IDEA
Step 1: Set Up Your PC Fan.
Find your self a working PC fan.
I used a 3" fan that I salvaged from an old PC I had laying around
1. Pull the black end off of the cables.
2. I did this carefully to keep the metal contacts in place, otherwise you'll be working with bare cables.
3. Optional : Clean the fan of all dust, I did this with a Q-Tip soaked in alcohol, just to make it look pretty :)