Visualising solid shapes

Objectives

   1. Understanding the difference between 2D figures and 3D figures

   2. Identify views of 3D objects

   3. Make a connection between everyday objects and 3D shapes

   4. Students will be able to describe 3D shapes

   5. Verifying Euler’s formula for Polyhedrons.

Estimated Time

90 minutes

Process (How to do the activity)

   1. "What are some shapes that you know?"

   2. Show picture of 2d and 3d and ask difference among shapes, What's the difference between 2D and 3D shapes?

   3. Invite students to share the names of 2D and 3D shapes

   4. What are 3 D shapes?

   15. Visualizing solid shapes is a very useful skill. You should be able to see ‘hidden’parts of the solid shape.

              Different sections of a solid can be viewed in many ways:

   (a) One way is to view by cutting or slicing the shape, which would result in the

      cross-section of the solid.

   (b)  Another way is by observing a 2-D shadow of a 3-D shape.

   (c) A third way is to look at the shape from different angles; the front-view, the

      side-view and the top-view can provide a lot of information about the shape

      observed.

      -Rotate the object to find a top, side and bottom view of the solid.

       Draw these views using pencil in your maths books, with a title "Top, side and bottom views of objects."

   5. Do you remember the Faces, Vertices and Edges of solid shapes

   6. Students recall the terms edge, vertex, and face.

      Face- part of a 3D shape that is flat

      Edge-two faces meet at a line segment( A line where two faces meet in 3D shape)

      Vertex- three or more edges meet at a point

      Base – the bottom base of a 3D shape

   7. Can you see that, the two-dimensional figures can be identified as the faces of the three-dimensional shapes?

   10. Observe that shapes have two or more than two identical(congruent)faces?name them?

   11. Which solids has all congruent faces?

   12.  What shape is the base of a cylinder?

   13.  Does the base of the shape change depending on how the shape is positioned?

   14. Observe the shape of each face and find the number of faces of the box that are identical by placing them on each other. Write down your observations.

Cuboidal  box – all six faces are rectangular, and opposites faces are identical. So there are three pairs of identical faces.

Cubical box – All six faces are squares and identical

Cylindrical Box – One curved surface and two circular faces which are identical.

A net is a sort of skeleton-outline in 2-D, which, when folded results in a 3-D shape.     

Euler’s formula : F+V=E+2 for Polyhedrons.