PIRA: 1D55.10

Equipment List

  • Plexiglas hoop with arch inside
  • metal sphere (1/2") or marble
  • ruler
  • overhead projector


  1. Place the hoop on the overhead with the cut side up. Spin the ball inside the hoop-note its path.
  2. Turn the hoop over with the cut side down. Again spin the ball inside the hoop and note its path after it leaves the hoop