The Galton Board is a 7.5” by 4.5” desktop probability machine. This device brings to life the statistical concept of normal distribution.
As you rotate the Galton Board on its axis, you set into motion a flow of steel beads that bounce with equal probability to the left or right through several rows of pegs. As the beads accumulate in the bins, they approximate the bell curve, as shown by the yellow line on the front of the Galton board. This hands-on Galton Board allows you to visualize the order embedded in the chaos of randomness!
Read the booklet here - http://galtonboard.com/Content/Instruction-Booklet.pdf
(yt user Lipm adds this explanation in the comments:
For those who might be interested in what’s going on, this is a demonstration of how the distribution of results from a series of binomial trials (in this case left or right) will tend towards the normal distribution when repeated enough. If it’s something that piques your interest, take a look at the central limit theorem; really interested bit of maths going on here.