Combine 3D Shapes

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SWBAT compose a new shape by combining three-dimensional shapes.

Big Idea

Bob The Builder look out! In this lesson, students will learn how to compose a new shape by combining 3D shapes.

Activating Strategy

10 minutes

I begin this lesson by reading “Captain Invincible and the Space Shapes”.  This book is great for introducing or reviewing three-dimensional shapes.  The cartoon art draws the students into this fun and exciting story that is a great vehicle for learning to recognize and define geometric shapes.


If the book isn't available, it can also be found on You Tube.

In the standard 1.G.A.2, some students may have difficulty with combining the 3D shapes, to help those students that have difficulty with this, my advice is to work with children to first identify the two shapes they will be putting together. Doing so will help them break down the shapes later on their own. I ask the following questions to help deepen understanding:

  • How is your new shape like the shapes you used to build it? How is it different?
  • Can you put together a sphere and another shape to make a new shape? Why or why not?

By allowing students to use concrete objects to help them conceptualize creating a new 3D shape, students will learn to make sense of problems (MP1).

Teaching Strategies

15 minutes

In advance, I have 3D shapes labeled and displayed. I then invite children to solve shape riddles.  For example:

  • I have 6 flat surfaces. Each flat surface is a square. I have no curved surfaces. What am I? (a cube)

I repeat with similar riddles to review each shape’s defining attributes.

I then display the Combine 3D shapes.ppt, and, using the first slide, I read aloud the problem this problem:

Mandy stacks one cylinder on top of another cylinder. Carl stacks one cube on top of another cube. What new shapes did Mandy and Carl make?

I hand out cubes and cylinders to students.  Having them work in pairs or small groups, I have children first model the problem with cylinders and cubes.

  • Does it matter where on the cylinder you stack the other cylinder? Why?  (Yes. They have to be stacked on their flat surfaces or they will roll.)
  • When you stack two cylinders, what is the new shape you get? How do you know? (a cylinder;  a cylinder has flat surfaces on both ends and one curved surface. So when you stack the cylinders on their flat surfaces, the shape is still a cylinder.)
  • When you stack two cubes, what is the new shape you get? How do you know? (a rectangular prism; a rectangular prism has 6 flat surfaces. Each flat surface is a square or other kind of rectangle.)

Then displaying the second slide of the PPT, I work through the model with children by having them use a cube and a rectangular prism to represent each of these three new shapes. Then give children time to find additional shapes.

  • How are the new shapes you made the same? How are they different? Possible answers: They all have flat surfaces. Some have more flat surfaces than others.

Independent Practice

30 minutes

Then I hand out the Combine 3D shapes_worksheets.docx and make sure children understand how to read the chart. I like to hand out 3D shapes to each student, but if there are not enough shapes available, I have children work in pairs or small groups and share the shapes.

Using the first problem on the worksheet, I ask the students:

  • How do you know which shape you can make? (If I can put the shapes together to look like the picture, then I can make it.)


5 minutes

To close out the lesson, I have students work in pairs and to combine two shapes to make a new shape. Then they describe how they put the shapes together to their partner.