A perfect pi party

20th May 2005 at 01:00
Our maths department decided to mark World "pi" Day, celebrating the number 3.14..., on March 14 (314 in the US), in style - and we made sure the whole school knew about it. We were popular in the staffroom and in our classrooms, thanks to pies, cakes, biscuits and sweets decorated with circles and 9, and cards with: "Happy pi Day!"

Year 9 made posters illustrating C = 9D and A = 9r2, which they pinned up around the school, and Years 10 and 11 practised their compass work by constructing accurate circumcircles and inscribed circles of triangles.

Some historical pi facts and figures were shared with all classes; especially amazing is the fact that "approximately 3" has been recognised as long as we have written records and is even mentioned in the Bible (Kings 7, 23; II Chronicles 4,2).

The sixth-form were able to construct circles and polygons using Cabri Geometry software, and we used their diagrams to give increasingly accurate approximations for 9 by calculating the areas of circumcircles and inscribed circles in terms of the radius of the circle. This linked to their current work when they had "to prove by integration the formula for the area of a circle".

One colleague took his last chance before retirement to play with Buffon's experiment, estimating pi by spinning needles on carefully ruled gridlines, then calculating the proportion of needles which crossed a line. He ensured pupil co-operation by rewards of Jammy Dodgers, and he was gratified that it worked so well, especially as, with health and safety in mind, he had used cocktail sticks instead of needles.

The pupils in the junior school were heard talking about the fun events, and for days afterwards every pupil could confidently explain that 9 is the ratio between the circumference and diameter of a circle - especially if a round jam and cream biscuit was on offer.

Andy McGinnes

Head of maths, Wellingborough School, Northants

Log-in as an existing print or digital subscriber

Forgotten your subscriber ID?


To access this content and the full TES archive, subscribe now.

View subscriber offers


Get TES online and delivered to your door – for less than the price of a coffee

Save 33% off the cover price with this great subscription offer. Every copy delivered to your door by first-class post, plus full access to TES online and the TES app for just £1.90 per week.
Subscribers also enjoy a range of fantastic offers and benefits worth over £270:

  • Discounts off TES Institute courses
  • Access over 200,000 articles in the TES online archive
  • Free Tastecard membership worth £79.99
  • Discounts with Zipcar, Buyagift.com, Virgin Wines and other partners
Order your low-cost subscription today