For this 1 Minute Finger Tip you'll need two pieces of thread (ideally in two different colours), a safety pin, and a long cardboard tube. When you're ready, start the clock! Begin by tying a safety pin to one end of one of the pieces of thread. Thread this down the tube... Take the next piece of thread and carefully thread it through the eye of a needle. Make a little hole in the bottom of the tube and thread through. Tie a knot on the end to prevent the thread from going right the way through the hole! Next, thread the second thread through the safety pin, and tie. Stop the clock! You've made a Ghostly Levitator - it seems to move up and down all by itself. It works because safety pin acts like a pulley. When you pull the thread at the bottom the tube moves upwards. And when you let go, it goes back down. It'll work best if you anchor the thread at the bottom to a table or under your foot. You can go sporty by applying the idea to make a basketball... ...it's exactly the same mechanism, but using a polystyrene ball instead.