The Levitron toy first appeared in the 1990s. The first versions just had a simple wooden box as the base, but over the years the design has improved, and as magnets have got stronger the top has been able to spin higher and higher.
How does it work? There are magnets in the base, and there is a magnet in the little spinning top. When the top is the right way up, the two magnets repel each other, and this is the force that is keeping the top in the air. However it will not work if the top is not spinning – it just turns over and is then attracted to the base. However while the top is spinning, gyroscopic stability keeps it upright, floating above the base. The top will spin for a few minutes, but eventually – slowed down by friction with the air – the top tips over and drops down onto the base.
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