Spin and stability
Hold a disc so that its edge is rubbing on the spinning table. As you relax your grip it will start to spin. If you let it go it will continue to spin and balance as it goes. If it is not knocked by something, it will stay up for some time much as a bike does when its wheels are turning. If the spin slows the disc will become less stable. Can you see how the spin alters between the centre and the edge of the turntable?