Flat Versus 3D
The biggest hurdle in figuring out how to teach children about three dimensional shapes is getting them to think beyond the flat surface
of a two-dimensional figure. From before children are even in school they are taught the shapes of circles, squares, triangles and rectangles, but much less time is spent on spheres, cones, pyramids and cubes. In fact, some of the tools used to teach the basic 2D shapes are in fact three dimensional objects. Toddler toy shape sorters, for instance, use three dimensional shapes such as cylinders in an effort to teach basic two dimensional shapes like circles. This confusion continues through early elementary education for many students as the terms and definitions of 3D shapes are nearly foreign to them.
3D Shape Grab Bag
A fun way to introduce the various three dimensional shapes to a class is through the use of mystery bags. In preparation for this lesson, teachers should find examples of different three dimensional shapes and place them inside paper bags. Ideally, one bag per student helps to reinforce this lesson with the entire class, but a sample selection can work well, too. Here are some ordinary household items that can be used to demonstrate three dimensional shapes.
- a wooden letter block for a cube
- an individual cereal box for a rectangle
- a rubber ball for a sphere
- a soup can for a cylinder
As each child opens their bag they should identify the item by its three dimensional shape, ie. a soup can would be identified as a cylinder.
Most kids love activities which include food, especially if they get to eat it. For this activity, teachers will need to be very open-minded and creative in how to teach children about three dimensional shapes as they will need to shop for foods that match this lesson. Here are some possible suggestions for 3D Food:
- Pretzel Combos, marshmallows, or cheese sticks for cylinders
- Donut holes or ball-shaped yogurt snacks for spheres
- Cheese cubes for cubes
- Toblerone candy bars as a possible three dimensional triangular shape
Getting Active with 3D Shapes
Another approach to teaching students three-dimensional shapes is to use large items that demonstrate shapes such as spheres and cubes. Large paper building bricks are available at many teacher supply stores and serve as a great demonstration for cubes. Students can stack and build these to construct various spaces throughout the classroom. Giving students time to work with the bricks will allow them to feel and consider the nature of three dimensional shapes. Requiring that they call the bricks "cubes" rather than bricks will help reinforce the new terminology of the three dimensional lesson. As for spheres, balls of different sizes can be used in a variety of outdoor games. Students can be given time to play with a large beach ball or small bouncy balls while requiring that they call the balls "spheres" to help reinforce the idea that these familiar objects are also three-dimensional shapes.
The Common Point to these Tips
The one common theme among these different suggestions is object lessons. Students should be given an opportunity to literally get their hands around familiar three dimensional forms to best see and understand the difference between 2D and 3D shapes.