Diamagnetic Levitation
Its Magic
I'm fascinated by the concept of something floating in mid-air without any visible means of support.
Matter can be either Diamagnetic, Paramagnetic, or Ferromagnetic.
Diamagnetism is a very weak repulsive force in the vicinity of a magnetic field. Almost everything we know is diamagnetic including water. Diamagnetic substance repels both the north and south poles of a magnet
Paramagnetism is a very weak attractive force in the vicinity of a magnetic field. The elements aluminum and platinum are paramagnetic.
Ferromagnetic material include the elements iron, nickel, cobalt, and gadolinium.
Bismuth is a chemical element that has the symbol Bi and atomic number 83. Is a heavy, brittle poor metal. In recent years Bismuth has been used as a non-toxic substitute for lead in shotgun shells and fishing sinkers.
Pyrolytic Graphite, also known as Pyrolytic Carbon, is a manmade material that has the highest diamagnetic properties known.
Silver
When I received my first shipment of Neodymium Magnets I immediately wanted to levitate something. Bismuth and Pyrolytic Graphite are not easy to find. I did, however, have some .999 fine silver in the form of 1 oz. Silver Eagles, the US bullion coin. I did achieve levitation but it wasn't very impressive. At least it was proof of concept.
Diamagnetically-Stabilized Levitation
Using Bismuth to Levitate a Magnet
Bismuth is gaining popularity with hunters and fishermen. Bismuth shot is replacing lead in shotgun shells because it is almost as heavy as lead and is non-toxic. Fishermen are using it for non-toxic sinkers. Waterfowl can eat it without toxic effects.
I lucked out when I went to my local Walmart and found a clearance sale on Bismuth Fishing Sinkers. I purchased several pounds of it for as little as 25¢ for an ounce to an ounce and a half bag. I melted some of it on my kitchen gas stove and made a bunch of Bismuth slugs followed by several levitation devices like the one on the right below. (I gave them all away so the pic is a computer graphic of the device.)
If you are very careful you can levitate a small magnet using only 1 piece of Bismuth. Here I molded a Bismuth disk then sanded it smooth before polishing it to a mirror finish. This gives it the appearance that it is floating twice as high as it really is.
You are better off using a coated lifting magnet as the liftee (I know that's not a real word, but it should be.) will inevitably fly up and smash into the lifter magnet at a pretty good speed. even a few layers of duct tape will cushion the impact so the small NIB won't smash to pieces.
Bismuth Crystals
There is another very cool thing you can do with Bismuth. You can make some unique, beautiful Bismuth Crystals. Check it out by clicking here.
Direct Diamagnetic Levitation
Floating Pyrolytic Graphite
Finally I found a source of Pyrolytic Graphite, the best diamagnetic material available. It is a manmade material made in such a way as to give it a single cleavage plane much like the mineral Mica. This means that you can use an Exacto Knife to split it into some very thin sheets. These sheet can be light enough and the diamagnetic properties are strong enough that it will levitate over some Neodymium Magnets all by itself.
The magnetic poles are alternating. If a magnets north pole is facing up then adjacent magnets must be south up like this.
N
S N
S N S
N S N
You can find several videos of this if you type in "Diamagnetic Pyrolytic Graphite" on YouTube search engine.
Diamagnetically-Stabilized Levitation
Using Pyrolytic Graphite to Levitate a Magnet
Pyrolytic Graphite works better when levitating a magnet than Bismuth. Most examples of this experiment on the Internet show a huge ugly contraption lifting a tiny (1/8" cube or similar small NIB). My question was "How do I get the most from the least?" I wanted a dainty structure levitating a decent size magnet. A magnet that you could see floating from across the room. I raised it up from the base to exaggerate the levitation effect. The Pyrolytic Graphite is supported by transparent Plexiglas.
Ultimately I found myself levitating a 3/8" cube using a 1/2" cube for the lifting magnet. That's a 0.053 cubic inch NIB being lifted by a 0.125 cubic inch NIB. The Liftee is 42% of the mass of the Lifter. Blowing at it through a soda straw can get it spinning rapidly for several minutes as there is no friction other than air resistance. Shining a small flashlight on it causes it to flash brightly. Shining a red laser light on the spinning magnet in a dark room created a neat effect. This is the ideal Desktop Executive Toy.
Direct Diamagnetic Levitation
Floating Pencil Lead (Graphite)
I was looking at my Magnet Bracelet one day when I decided to try to make a device and see if I could levitate pencil lead, a form of graphite which should have decent Diamagnetic properties These NIBs are 1/4" dia by 1/2" thick and are Diametrically Magnetized. That means that the poles are on the side of the cylinder as opposed to the flat ends. The pencil lead is 0.7 mm in diameter.
Much to my surprise it worked the first time. Not all pencil leads float. This graphite came out of an inexpensive Papermate mechanical pencil.