Exploring 3D Objects

We have been working with 3D objects with Mrs S. 3D means that an object has 3 dimensions. We can measure it three ways. One of the things that we did was to make a cube which is a very special rectangular prism. A cube is a prism where all the faces and edges are the same.

By Cube.svg: Image created by H McKenna based on source code by Marcelo Reis.derivative work: Cristianrodenas (Cube.svg) [CC-BY-SA-2.5], via Wikimedia Commons

We used rectangles to create our cubes and needed 12 rectangles for each cube. We needed to fold each rectangle in half before gluing them together to make our cubes. We were able to see the insides of our cubes as the faces were not solid.

Creating cubes from rectangles

Creating cubes from rectangles

Once we worked out the construction technique we modified our design by making it smaller or larger or changing the shape. One group managed to make a triangular based pyramid. It is almost a tetrahedron but it does quite fit the definition of this 3D object as each face is not quite the same size.

When we were creating our transformations of the cube one group made a very large cube which is now hanging up in our classroom. They worked carefully to measure out each rectangle needed to created their very big 3D object.

DSC00894

We did not use the usual technique for making 3D objects. This is to create a net using the 2D shapes that are needed to make the 3D object. The net for a cube is 6 squares and there is more than one way that the squares can be arranged so that they fold up to make a cube.

How many different nets do you think there are for creating a cube? What shapes would you need to create a net for a square pyramid?