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Mar. 12, 2014

Estimate Pi by Dropping Sticks

by Chau Tu

Click to enlarge images
Pi Day is just around the corner (March 14, or 3.14), and we here at SciFri came across a fun simulator that estimates the number in a blog post by Tommy Ogden, a Ph.D student in theoretical physics at Durham University in England.
 
The simulator is based on an experiment called Buffon’s needle, one of the oldest problems in the field of geometrical probability, according to The Mathematica Journal. In the 18th century, French philosopher Georges-Louis Leclerc, Comte de Buffon determined that you can approximate pi by dropping needles on a grid of parallel lines (whose spacing is greater than the length of a needle) and calculating the probability that they will cross a line. The probability is directly related to pi. 
 
Ultimately, you can calculate pi using this formula: 
{"input":{"width":490,"photo":"pi","row":"4874","table":"DOCUMENT"}}
 
Ready to find pi? Use Ogden's simulator below, where you can "drop" thousands of sticks and test the formula yourself. How close can you get to pi, with how many sticks? Send us your results by commenting below or tweeting us @scifri with the hashtag #MyPi.
 
If you want to get truly interactive, print out this worksheet and drop 2.5-inch toothpicks on it. Let us know how close you get!  Please note that an updated version of this worksheet was added at about 6:30 p.m. on March 13, 2014 to reflect a change in the formula.

Bonus: You can even try the experiment using hot dogs!

 

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About Chau Tu

Chau is SciFri's web producer. She spends a lot of her time drinking coffee, seeking out street art, listening to music, and defending Los Angeles. You can find her on Twitter @chaubtu

The views expressed are those of the author and are not necessarily those of Science Friday.

Science Friday® is produced by the Science Friday Initiative, a 501(c)(3) nonprofit organization.

Science Friday® and SciFri® are registered service marks of Science Friday, Inc. Site design by Pentagram; engineering by Mediapolis.

 

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