This week the children enjoyed constructing their own 3D ‘skeleton’ shapes to explore their properties. Plasticine acted as the vertices (corners) and straws or lolly sticks were used to create the edges, which are found where faces meet. Once the shape was formed, the children were able to check the number of faces, which are the individual surfaces of a shape. Following further investigation, we uncovered Euler’s formula for 3D shapes. This states that Faces + Vertices - Edges = 2. However, the children found out that this rule only applies to shapes called polyhedra. A polyhedron is a closed solid shape that has flat faces and straight edges. Therefore, the pattern did not work for shapes such as a cylinder or hemisphere, as they have curved faces and edges.