What is Bean machine?
[[File:Planche de Galton.jpg|thumb|A Galton box, with some balls]] [[File:Galton Box.svg|thumb|A schematic view. At each pin, the ball is equally likely to go left or right.]] The '''bean machine''', also known as the '''[[quincunx]]''' or '''Galton box''', is a [[machine]] invented by Sir [[Francis Galton]] to demonstrate the [[law of error]] and the [[normal distribution]]. The machine consists of a vertical board with interleaved rows of pins. Balls are dropped from the top, and bounce left and right as they hit the pins. Eventually, they are collected into one-ball-wide bins at the bottom. The height of ball columns in the bins approximates a [[normal distribution|bell curve]]. Overlaying [[Pascal's triangle]] onto the pins shows the number of different paths that can be taken to get to each pin. A large-scale working model of this device can be seen at the [[Museum of Science, Boston]]. {{science-stub}} [[Category:Engineering]]