Lesson 8

Pattern Block Symmetry

Est. Class Sessions: 2

Summarizing the Lesson

After students finish the pages, have them discuss their experiences

Return to the question asked at the beginning of the lesson:

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  • What does a symmetrical picture look like?

Direct students' attention to the notes they generated on chart paper at the beginning of the lesson. Add to the notes as appropriate.

  • A figure with line symmetry has two halves.
  • The two halves match exactly.
  • One half is flipped over the line of symmetry.
  • A line of symmetry will divide the two halves.

Place pattern blocks on the display as shown in Figure 4.

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  • How do you know if this shape has a line of symmetry?

Suggest to students that they themselves are symmetrical. Ask them to imagine a line going straight down the middle of their faces. Have them name the features that are the same on each side of the line. (e.g., one eye, one ear, half a nose and mouth, etc.) Point out that this imaginary line is also a line of symmetry, even though it is not visible.

Draw one half of a heart on the display. Ask:

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  • Can you predict what the other half will look like?

Draw the second half of the heart and show the line of symmetry.

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  • Can you think of other things that have line symmetry with an invisible line of symmetry? (e.g., butterfly, donut, the letter B, an equilateral triangle, the letter T, a leaf)
  • How can you tell if something is symmetrical if it doesn't have a line of symmetry showing? (Possible response: You can fold it in half. If the two halves are the same, the object is symmetrical.)
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Young students sometimes draw a conclusion from activities like these that a picture is not symmetrical unless they can actually see a line drawn down the middle of it. In your discussion of the activity pages, add examples of symmetrical figures or objects that have an imaginary line of symmetry, not an actual visible line.

Student Guide:
Student Activity Book:
Master:
Shape with one line of symmetry
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