Tuesday, June 19, 2012 7:40:58 PM
Its a trick with sound and magnets. The pitch of the sound raises the cup, but its outside our audio spectrum that we don't hear it (like a dog whistle, just opposite end of the scale) and magnets are used to stabilize the cup.
Tuesday, June 19, 2012 5:10:17 PM
I imagine the thread was laid across the top of the cup, and then the lid placed over that, leaving thread hanging on both sides. This allows the thread to be horizontal (hand passed over the top) and keep the cup from rotating. The ends of the thread are anchored to the sides of the car.