How Round is Your Circle? – A Maths Revolution advocated by Dr Chris Sangwin


On Thursday evening, OxTrad welcomed fan-favourite guest speaker Dr Chris Sangwin once more to Corpus Christi. Chris is the Professor of Technology Enhanced Science Education at the University of Edinburgh, researching the automatic assessment of mathematics using computer algebra and problem solving using Moore method and similar student-centred approaches.



In an interactive presentation, Chris first invited students to the board to display their best attempts at hand-drawn circles, before asking the audience for their ‘favourite circle’. There followed an investigation into perceptions of roundness filled with mathematical circular conundrums and other assorted revelations. Posing the question of ‘how do we define a circle or a sphere’, he suggests that the traditional concept of constant diameter might not hold up in light of recent research. Instead, he argues that whilst the constant diameter argument is still necessary, it is no longer sufficient as mathematicians discovered a new shape (Meissner’s Tetrahedron) which has a constant diameter but is not a circle.