Prisms, prisms all around us!
In year 3 shape the main new 3D shape to be able to recognise and describe is the prism. A prism is a shape that has the same cross section and the same size throughout its length. Some shapes, such as cones and square based pyramids have the same shape throughout their length (ie circle and square respectively) but they are not prisms because the size of the circle or square changes as you move from one end to the other.
There are many prisms to be found in the home (eg rulers, pencils, cans, chocolate boxes etc) although they often have a small part such as the point of a pencil which prevents them from being a pure prism. Children can generally be allowed to ignore these annoying parts that manufacturers insist on adding to spoil our fun with maths!