Buffon's-needle pi tray — 3D-printable model preview

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Science & education Medium

Buffon's-needle pi tray

Estimate pi by dropping matchsticks on a tray of parallel lines

In 1777 the Comte de Buffon found a way to work out pi with nothing but sticks: drop sticks as long as the gap between parallel lines, and the chance that one lands across a line is exactly 2 divided by pi. Drop 40 mm sticks onto this tray, which has raised lines exactly 40 mm apart, count how many you dropped (N) and how many cross or touch a line (C), and pi is about 2N divided by C. A hundred drops gets close to 3.1; a whole class pooling results gets closer still.

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Size: 210 × 210 × 12 mm
Shape: Rectangular
Walls: 2.4 mm
Volume: 116 cm³
Est. weight (PLA): 144 g
Parts to print: 1
Category: Science & education
Made by: Krypto
Built in: 25 steps

What’s in it

Rectangular, 210 × 210 × 12 mm, with 2.4 mm walls
4 dividers
Raised text: “PI ~ 2N ÷ C”

How to print it

Cut matchsticks or cocktail sticks to 40 mm, the same as the line spacing. Drop them from 20 cm, about 20 at a time.

Prints as shown on its floor, no supports.

Filament: at most about 144 g of PLA printed solid (roughly $2.88 at $20 per kg); normal infill uses less.

To get the files, open it in the generator and choose File › Download STL (one file per part) or Download 3MF (every part on one plate).

Questions

What size is the buffon's-needle pi tray model?

The buffon's-needle pi tray model measures 210 × 210 × 12 mm (width × depth × height). You can change every size in the free SO3D.xyz generator before you download it.

Does it need supports?

No. Cut matchsticks or cocktail sticks to 40 mm, the same as the line spacing. Drop them from 20 cm, about 20 at a time. Prints as shown on its floor, no supports.

How much filament does it use?

At most about 144 g of PLA (116 cm³ printed solid), roughly $2.88 of filament at $20 per kg. Normal infill uses less.

Can I change it?

Yes. Open it in the SO3D.xyz generator (free, in your browser), change the size, walls, dividers, holes, text or anything else, then download it as STL or 3MF for your slicer.

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Make it fit your space

Change the size, walls, dividers, holes and labels of the buffon's-needle pi tray model in your browser, then download it for your printer. Free, no CAD needed.

Customize this model