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Happy Fibonacci Day!

Updated: Mar 15, 2021

What does a 12th century mathematician have to do with a pineapple? Today is Fibonacci DayNovember 23, or 11/23, the first numbers in the Fibonacci sequence (1, 1, 2, 3).

Born in Italy around 1170, Leonardo Bonacci (nicknamed Fibonacci) never would’ve even laid eyes on a pineapple, but the sequence of numbers he discovered can be seen throughout nature, from seashells to pine cones to the human ear. And the sequence is used in everything from financial trading on the stock market to music and art.

The Fibonacci sequence begins with 1, 1, 2, 3, 5, 8, 13, 21… and so on. Each next number in the sequence is the sum of the two numbers that precede it. For example, 1+1=2, 1+2=3, 2+3=5, and on and on.

Okay, but what about the pineapples?

These fruits have Fibonacci numbers all over them:

  • 8 rows of scales spiralling gradually

  • 13 rows of scales spiralling at a medium slope

  • 21 rows of scales spiralling at a steep slope

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Don’t believe us? Try it yourself! Use a toothpick to mark a starting place on the fruit and count the number of scales along that spiral.

How’s that for a fun (and sweet!) Fibonacci fact?

For more fun STEAM experiment ideas, follow NII Explore on Instagram. And have a happy 11/23!


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