Students develop a model to represent the collision of two black holes, the gravitational waves that result and the waves' propagation through spacetime. Materials Gelatin (clear or yellow) Baking pan (clear, smooth glass preferred) Cutting board, cookie sheet or other flat, portable surface Small mirror Two small steel marbles, ball bearings or round pebbles Laser pointer (red or green laser) Laser Target Card - Download PDF Management The model can be developed in pairs, small groups, larger