2D Shapes on 3D Shapes

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Objective

SWBAT identify the two-dimensional shapes that make up the faces of three-dimensional shapes.

Big Idea

In this lesson, children learn to identify and distinguish the shapes of the flat surfaces of three-dimensional shapes.

Activating Strategy

10 minutes

I start this lesson by handing out 3D shapes and play-doh to each student, or pairs of students.  I review which shapes have flat surfaces.  I instruct the students to press the flat surface of their 3D shapes into their play-doh.  We have a class discussion about the different types of 2D shapes that are made using 3D shapes.

Warning: this is a very fun, tactile, and (potentially messy) activity! I make sure to warn students ahead of time that any silliness with the play-doh will result in, you guessed it, no more play-doh.

For the standard G.A1, I have found that some students may have difficulty recognizing the two-dimensional shape on the three-dimensional shapes.  To help overcome this, students press the flat surface of their 3D shape into the play-doh.  This allows for them to see the 2D shape that makes up our 3D shapes.  Thus, the activity makes the abstract visualization more concrete.

Teaching Strategies

15 minutes

Then using models of 3D shapes, I instruct students to look at their cone.  I read the following problem aloud:

Lee places a cone on a piece of paper and draws around its flat surface. What shape did Lee draw?

Then I have children hold a cone and turn it around in different ways to observe its surfaces. Make sure all children have a chance to hold and turn the cone.

  • How many flat surfaces does a cone have? (1 flat surface)
  • How can you trace around the flat surface? (I put the flat surface down on the paper, and then I draw around where the shape meets the paper.)
  • What other kind of surface does a cone have? (a curved surface)

I then display the first on the 2D shapes on 3D shapes.ppt.  I work through the model with children and make sure they understand that the six rectangles represent the six flat surfaces of the rectangular prism. I have children trace around each side.

  • How are the shapes you drew alike? How are they different? (They all have four sides.  The rectangles are not all the same size.)

Independent Practice

30 minutes

Students complete a 2D shapes on 3D shapes_worksheet.docx for the independent portion of this lesson.  I work through the first question (slide 2) with the students prior to letting them work independently.  

Closing/Summarizing

5 minutes

To close out the lesson, I have students write in their journals to tell me which 2D shape is found on the following: cube, cone, cylinder, and rectangular prism.