Plinko (Galton Board, Binomial Distribution, Bernoulli Trials)

Plinko (Galton Board, Binomial Distribution, Bernoulli Trials)

The Plinko Game, also known as a Galton Board, is a fascinating tool for students to experience and think about the laws of probability. For example, if you toss four fair coins, what is the probability that you end up with 2 head and 2 tails? In other words, if you drop a ball into the plinko opening, how likely is it going to the middle drawer? This type of problem is related to the binomial distribution, combinatorial counting, Pascal’s triangle, etc.

The Plinko design here has four layers and measures approximately 127mm x 110mm x 86mm, meaning it can be printed on most small 3D printers. The space between the pins is 16.1mm, allowing the use of marbles that is less than 16mm in diameter. Two balls, measuring 15mm and 15.8mm in diameter, are included. For easy printing, the balls are split into halves with internal adjustments for easy printing and assembly. If the connector is not tight enough, a drop of glue might be useful. Standards marbles work just as well.

Warning: Small parts can be dangerous for children when swallowed; please educate children not to put little things into their mouth and follow all safety rules when working with young children. Have fun!

References

1. https://en.wikipedia.org/wiki/Bernoulli_trial
2. http://mathworld.wolfram.com/GaltonBoard.html
3. https://phet.colorado.edu/en/simulation/plinko-probability

Res: .1mm to .2mm, no support or raft.