Gadget Freak case #122: Cutting pumpkins the Tesla way:
Rick Crammond created a gadget for cutting Halloween pumpkins that is powered by the faucet in a kitchen sink. The water pressure drives a stack of CDs that has been converted into a turbine. Crammond's Tesla CD Turbine uses two principles developed by Nikola Tesla in the early 1900s. The turbine uses flat discs rather than blades or cups.
In Crammond's gadget, the discs are CDs or DVDs stacked in their cases. Crammond adds a few other household items -- such as Krazy Glue and glue sticks -- and hooks it all to a kitchen faucet using a garden hose. The result is a surprisingly powerful turbine. Crammond uses that turbine power to drive a skill saw blade for easy pumpkin cutting.