Ping Pong Pendulum

Warning! Adult supervision required: some small parts Laser pointer included: do not shine in eyes Please read the procedure before beginning! After reading, please watch the video. Some activities require more time and cleanup than others. You also have the choice of performing these activities in a way that suits your needs.



  • Laser pointer
  • Washi tape
  • Hair Diffraction
  • Paper cup
  • Strand of hair (not included)

Hair Diffraction

1. Poke a small hole through the center of the cup’s bottom.

2. Pluck out a single strand of hair, and stretch it tight across the center of the small hole (hair works best, but an extremely thin piece of string can work).

3. Tape the hair to the cup’s bottom on both sides of the hole. Make sure no tape covers the hole—the only thing across the hole should be the hair.

4. Hold the cup in one hand (with the bottom pointing towards you) and the laser pointer in your other hand.

5. Facing a wall, shine the laser through the hole in the cup. The effect might be easier to see in a dark room.

6. Do you see an unusual laser pattern on the wall? How does this pattern change as you move closer to or further from the wall?

Mirror Maze

  • 4 mirrors
  • 4 corner braces
  • Large template paper
  • Small target paper

Mirror Maze

1. Remove the adhesive backing and protective plastic from each mirror.

2. Stick one corner brace to the bottom-center of each mirror’s sticky back. The brace forms a stand and allows the mirror to stand up.

3. Place the large piece of paper inside the bottom of your box. It should fit fairly snug—feel free to tape it down with the washi tape if needed.

4. Tape the target paper to a short wall inside your box. The large piece of paper tells you which short wall to use—it should be the side opposite the OH WOW! logo on the large paper.

5. Place your four mirrors (with stands) on the spots indicated on the large paper. You can tape down the stands to the paper to help prevent the mirrors from tilting down.

6. Place your laser pointer in the position marked on the large sheet of paper. Feel free to raise it by placing it on top of an object, such as your roll of washi tape.

7. Turn on your laser! Did you hit any of the targets? Try changing the angles of your laser and mirrors to hit each of them!