The Galton Board

The Galton Board is a desktop ‘probability machine’ incorporating the 1873 invention of Sir Francis Galton. It demonstrates the mathematical concept of binomial distribution by approximating the statistical concept of normal distribution. As you rotate the transparent assembly, you set into motion the flow of 6,000 steel beads captured within the upper reservoir. As the beads cascade downward through a matrix of hexagonal pegs, they have an equal probability of bouncing to the left or right. When the beads accumulate in the lower 15 bins, overall they approximate the shape of the Bell Curve.