LEVITRON - ANTIGRAVITY DEVICE

Levitating the Levitron is not trivial and can be difficult to learn. First, a plastic plate is placed on top of the magnetic base, and the top is spun on the plate. Then the plate is lifted by hand until, if all the conditions are right, the top rises above it to the equilibrium point. If the top is too heavy, it cannot rise above the plate; too light, and it flies off. Washers of various masses are thus included in the kit that can be placed on the spindle of the top to adjust its weight. The spin rate of the top must also fall within a narrow range around 25 rotations per second. Since it can be difficult to spin the top fast enough by hand, Creative Gifts makes a battery-powered, handheld device to spin the top with an electric motor. After a few minutes, the top falls when air friction slows it below the critical speed.


The stability of the Levitron cannot be explained if the top's axis has a fixed direction in space. Stability against flipping is not enough. Gyroscopic precession around the local magnetic field direction is necessary. An analysis and numerical integration of the equations of motion for an experimental stemless top that includes gyroscopic precession around the local magnetic field lines predict that the top will be supported stably up to spin speeds of about 3,065 rpm. An upper spin limit of 2779 rpm for this top is observed experimentally and explained as an adiabatic condition. Spin stabilized magnetic levitation is a macroscopic analog of magnetic gradient traps used to confine particles with a quantum magnetic moment.