Archive February, 2018

Giant Sphere

27 February, 22:27, by EvaB

Sean Sinclair made a giant geodesic sphere for the math club  at St. Mary’s High School in Kitchener.  He has been making lots of smaller spheres of different geometries for a while, but this one is amazing!

The internal diameter of the sphere is 1830 mm (72 inches), while the external diameter is 1930 mm (76 inches).  It is based upon Geodesic pattern Number 4  (, which is essentially a soccer ball (truncated icosahedron), with additional sides going into the centre of the pentagons and hexagons, from the outer vertices.

There are three different lengths of arcs, which are labeled as follows:  P – centre of the pentagons, H – centre of the hexagons, S – edges of the hexagons and pentagons (the soccer ball).

There are also three different corner connections:  five equal divisions for the centre of the pentagons, six equal divisions for the centre of the hexagons, and six uneven (two smaller and four larger) for the junctions between two hexagons and a pentagon.