Recently I was invited to take a mathematical puzzles stall to the East Midlands Big Bang science fair. This took place in Nottingham yesterday. I gathered a few friends from the Nottingham MathsJam group, which I run, and we planned what we could do with a stall. We agreed a list of puzzles we could put together and run. We felt it was important to have solid, physical puzzles and games that would attract people to the stall, including making use of the floor area, as well as more advanced and intriguing items and a takeaway sheet. I wanted the takeaway sheet to provide some advice on problem solving techniques as well as some puzzles to try. There were various extra constraints as well as what we could physically make with no budget, including the difficulty of catering to the wide age range of those attending: 9 to 19!

We met a couple of weekends ago and agreed a set of puzzles, tried them on fellow MathsJammers at the monthly meeting last week and have spent the last week or so making bits and pieces ready for the fair yesterday (particular thanks in that regard are due to John Read and Kathryn Taylor). We called the stall “Solving it like a mathematician”. For big, attractive, fun we had Latin squares with giant playing cards, a puzzle involving arranging tokens inside a giant circle (a hula hoop) and matchstick puzzles with giant matchsticks (bamboo canes). For hands on activity we were making Möbius strips. The more in depth tabletop exercises included: Buffon’s needle for estimating pi (we got 3.78 from 141 throws); a ‘wisdom of crowds’ guessing how much rice is in the jar and rice on the chessboard exponential growth combo; and, the fifteen puzzle and how to tell if an arbitrary position can be solved. Each puzzle had an advice sheet and these as well as the handout are available on a page on my website.

I have been unwell recently so I took a lighter load than I might have for the day. I helped set up the stall and stayed for the first hour, in which not much was happening, then left until the afternoon. Here is a picture of the stall, ready to go but sans visitors.

After the first hour, I left the stall in the capable hands of John Read and Ian Peatfield for the morning. We had agreed a kind of shift system – I didn’t want everyone arriving first thing and us all getting tired mid-afternoon. I went and found a cafe for a quiet read. When I returned after lunch Ian had finished his stint, Alex Corner and Noel France had joined John, and the stall was abuzz! Here is a photo.

Apart from the combination of bamboo cane ‘matches’ and plastic plate ‘coins’ for some of the oversized puzzles leading to a plate spinning class, everything was going as planned. Soon we were joined by Kathryn Taylor and the five of us spent the afternoon rushing around after wave-upon-wave of pupils. That every few minutes another pupil was dragged away from the stall, “put that down now, we’ve got to leave”, by their teachers was, I think, a sign of success. Here’s one more picture from the afternoon.

Overall, I am very pleased with the stall we made and the team who ran it. My first science fair and a very pleasing experience indeed. I hope some of our visitors saw some interest in mathematics and the couple of hundred who took the advice sheet might learn something about approaching problems. Now, to find somewhere to store my new ‘puzzles stall kit’ for next time!

Congratulations should go to David Ault and his team for organising the fair which, as far as I can tell, went very smoothly.