A fluidized bed is a mixture of a solid and a fluid that behaves like a fluid. To show us how it works, Mark Rober mixed sand with bursts of air – when the air is piped in, the sand behaves like it’s a fluid. Just for kicks, he also made a larger bed using a discarded hot tub.
Mark Rober teamed up with Eclectical Engineering to create this awesomely unwieldy weapon which fires huge foam darts, made from pool noodles and toilet plungers. Thanks to compressed air, it can fire darts at speeds up to 40 mph. Check out the gunpowder upgrade.