Geometric form of rectangular prisms
Figure 10: Rectangular prisms with layers of cubes
My students will understand that the space inside a solid shape like a rectangular prism is called the volume. I will have my students examine examples of real life geometric solids, so they can understand the volume: cereal boxes (rectangular prisms), soda cans (cylinders or circular prisms), ice cream cone (cone). I will compare and contrast the surface areas and volumes of these solids so we can begin to understand the different aspects of formulas: length, width and height. Students will learn the volume of rectangular prisms by counting the number of cubes needed to fill the prism, starting with a rectangular layer on the bottom, and working up, layer by layer, to the number of layers needed to fill to the top of the prism (see figure 10). This visual representation of volume using layers of rectangular arrays of counting blocks will help the students as they begin to use formulas for volume V = L ∙ W ∙ H. I will emphasize the analogy with the area of a rectangle. The process is similar, but now there is a third dimension to worry about.
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