Last week, a "self sustaining electrical turbine generator" was found on Kickstarter. Another name for the product is a perpetual motion machine. (We saw this story first on GigaOm.) Put simply, a ...

Perpetual motion devices are either a gag, a scam, or as in the case of this particular toy that [Big Clive] bought on AliExpress, a rather fascinating demonstration of a contact-free inductive sensor ...

Let's start with a water wheel in still water with an electric generator hooked up to it. Let's say it has a ratchet wheel so it can only turn in one direction. I want to calculate the probability ...