In this clip from Genius by Stephen Hawking, three volunteers discover the randomness of the quantum world using a Geiger counter, radioactive decay, and a machine that shoots wet sponges. The volunteers are faced with a challenge of randomness, using a Geiger counter connected to a box containing a weak radioactive source. This source emits particles of radiation which the Geiger counter is able to detect. When the counter detects the gas, it triggers the wheel to stop randomly and fire a sponge out of the cannon at one of the three volunteers. Subatomic particles behave randomly and there is no way of knowing when the sponge will be released. This is because radioactive decay is an entirely random and unpredictable process. However, there are only three possible outcomes to this experiment. This highlights how the universe is random but only within a fixed set of possibilities.