In this fascinating model children can levitate a CD magnetically. Take a CD box base with a 4-cm tall central stem. Stick ring magnets with the same poles up along the periphery of two CDs. Place both CDs with the magnets facing each other.
Do it details
Image for your reference
As the same polarity magnets face each other the CDs repel and the top one levitates. Once spun the top CD keeps rotating for a very long time.