Levitating Diamagnetic Carbon-Graphite Over Magnets
This is a brand-new experiment for us. We were amazed at how well it worked! We are currently working on more experiments with this phenomenon, and attempting to get higher and more dramatic levitation.
To perform this demonstration, we stacked 16 N-I-B cube magnets and let them stick themselves to a smooth steel surface to increase the field. The magnets are our Item #24, an N-45 grade 3/16 inch gold-plated cube magnet. The magnets must be arranged with the proper polarity--looking down on the top of the magnet stack, the polarity should be:
The Carbon-Graphite chip was cut from a larger chunk using a home-made hole saw and a cordless drill. The hole saw was simply a broken-off piece of hollow metal radio antenna that we broke off from DanB's boom box. We carefully sanded the chip down to about .020 inches thick; it was about 1/8 inch in diameter. According to others who have performed this experiment, it makes a difference which axis you cut your chip out of. We cut in through the thin dimension of the Carbon-Graphite block, but are performing more experiments to see which axis works the best.
It also seems to make a difference what shape the chip is. In our case, when we used a chip with corners on it, the corners aligned at 45 degrees to the magnet stack, putting them over the weakest magnetic field from the magnets (the flat surface). For this reason, we chose to use a circular piece of Carbon-Graphite as the corners were just dead weight, and we did achieve higher levitation (nearly .030 inches) this way. However, another person who replicated this experiment using a different variety of Carbon-Graphite found that the corners aligned at 90 degrees, right over the cracks between the magnets; in his case the corners helped the levitation effect. We do not know yet if this is because of differences in the Carbon-Graphite used, or the axis from which the chips were cut.