Physics · Study 024
Galton Board
Balls bounce left or right at each of twelve pegs and pile into bins that trace the binomial distribution. Tilt the odds with your pointer.
What you're looking at
At every peg a ball goes right with some probability and left otherwise. After twelve rows its bin is simply the number of times it went right. The blue outline shows the binomial prediction for the current odds, and the orange bars grow to fill it as more balls arrive.
The idea behind it
Francis Galton built the first of these in the 1870s to show how a bell curve emerges from many small independent chances. It remains the most direct physical picture of the central limit theorem: no ball knows about the curve, yet the crowd draws it every time.
Try this
Move the pointer left or right to bias every bounce. The pile and the predicted curve shift together.
