If you like it, but don't have the laser access or don't want to do the casting, follow the links at http://www.cadabralabs.com to get a kit.
In this instructable, we build a diamagnetic levitation sculpture, complete with easy adjustments for optimizing the levitation of the small cube magnet. The instructions are fairly complex, and need a number of tools, but the end result is very nice! See http://www.youtube.com/watch?v=W_hgNbEqVlE for a video of it in action!
How does it work?
We've all tried to get one magnet just the perfect height above the other so that the magnetic pull matches gravity, and the bottom magnet floats, but while this may be possible in theory, this would only work in a micrometer range of distances. Even if you had something more steady than your hand holding it, any slight vibration would move it enough to move it out of that range. So how do we do it here?
The bismuth we're using above and below the bottom magnet is diamagnetic. This means it very weakly repels any magnetic force, but the stronger that force, the more it repels. When you get the lifter magnet far enough away that its just barely far enough away from the cube magnet to lift it, the bismuth pushes it down until the cube is far enough away from the bismuth to be affected by it. At that point, the bismuth below is close enough to the cube magnet to push it back up slightly. All you need to get it floating is find the right balance of the distance between the two bismuth tubes, and the lifter magnet above! Both of those are adjustable in this project!
About 1 square foot of 1/8" MDF or baltic birch plywood.
Access to a laser cutter capable of cutting through 1/8" MDF or plywood; alternatively you could use a jigsaw if you're a very accurate jigsawer.
1/10th lb of bismuth. You might find this sold as fishing weights or online.
Pan to melt bismuth.
Casting forms to cast the bismuth into nice round shapes.
Sandpaper to smooth out the casts. (Not necessary but recommended)
1 5/16th" elevator bolt.
1 5/16th" nut.
1 5/16th" locking nut
2 6-32x3/4" bolts
1 6-32x1.5" bolt
4 6-32" nuts
1 strong nib lifting magnet.
1 3/16th" strong nib floating magnet
Step 1: Step 1: Cast the bismuth
The mold you use can be made pretty easily with some tin foil. Simply find something with a hole half an inch across, and carefully push the tin foil into the hole, pressing around the inside of the hole to get it as smooth as possible. You can either leave it in the hole (it will get a bit hot) or gently pull it out. It should hold its shape fairly well.
Melting the bismuth:
Bismuth melts at a pretty low temperature, so you can actually melt it on your kitchen stove. Alternatively, you can use a propane torch, but that's overkill.
Once the bismuth is melted, carefully pour it into your mold. Before the bismuth solidifies, stick the 6/32x1.5" bolt halfway in as straight up as posible, being careful not to burn yourself. It should only take a minute for it to cool down, but you can run water over it to speed up the cooling. Once its cooled, carefully unscrew the bolt out, and repeat the process with a second mold.
At this point your bismuth cast is going to look pretty rough. Use some rough sandpaper to get the big imperfections removed, and then finer sandpaper to remove the smaller ones. With a bit of work, you can make it look really nice. The most important part is making the top (away from the bolt hole) smooth and flat.