Symmetry+Lesson+Plan

ELD 308

Symmetry Lesson Plan

 * Grade**: 5


 * Time:** 40 minutes

4. Classify two-dimensional figures in a hierarchy based on properties.
 * Standard:** Common Core Standards, Mathematics (p.38)


 * Objective:** Students will identify figures as symmetrical or non-symmetrical based on whether the two halves of a figure are exactly the same. Students will use vocabulary like: congruent, line of symmetry, symmetrical. Students will discover that two-dimensional figures may have more than one line of symmetry by identifying all the lines of symmetry in a figure.


 * Materials:**
 * Symmetry in Shapes worksheet
 * Symmetry in the Alphabet worksheet
 * Large pre-measured shapes (construction paper)
 * Large enough for demonstration
 * Small enough to be used as manipulatives
 * Overhead projector
 * Overhead sheets with pre-measured shapes that coincide with those on the worksheet

1. Anticipatory Set (Engagement)
 * Lesson Sequence:**
 * “Students, not too long ago we finished our unit on Geometry. We learned about rays, lines, line segments, and we began to look at flipping or rotating shapes. Also, we learned about whether or not shapes are congruent to one another. What does it mean for a shape to be congruent? What different

2. State objective and purpose
 * “Today we are going to look at different shapes and identify whether they are symmetrical or not.”

3. Teach and Model
 * What do you know about symmetry and symmetrical figures? Congruent means that two figures are exactly the same: same size and same shape. Symmetrical means that two halves of a figure are exactly the same: same size and same shape. A symmetrical figure has two halves that are congruent to one another.” Write definitions on the board (and have students write the definitions in their math notebook).
 * “I’d like you to take your worksheet that says ‘Regular Polygons’ on the top of it. Take this piece of paper and fold it exactly in half. Are the two halves congruent? Tell me how you know.”
 * “So, according to our definition of symmetrical, this piece of paper is symmetrical because we can fold it in half and we find that the two halves are congruent.”
 * “Now, open up your paper and draw a line along the fold in the paper. This line is your line of symmetry. After doing this, what can you tell me about what a line of symmetry is?” A line that divides a figure into two congruent parts. Write definition on the board (and have students write the definitions in their math notebook).
 * “Please take out your rulers and let’s take a look at your Regular Polygons worksheet. The first figure is a triangle. Use your ruler to draw a line of symmetry through the triangle.” Discuss.

4. Independent Practice/Assessment
 * “Try a few of these problems on your own. Draw a line of symmetry to show whether the shape is symmetrical or not. You have five minutes, so just do as many as you can and we will talk about them.”
 * After the 5 minutes is finished, go over different shapes on the overhead projector. Have students come up to the projector to show the lines of symmetry they found.
 * Overhead sheets should have pre-measured shapes on them that coincide with the shapes on the worksheet. Also, each student that comes up to the projector to show lines of symmetry should use a different color marker.
 * Define shapes as symmetrical or non-symmetrical
 * If students have not discovered multiple lines of symmetry, rotate a shape and ask whether the class sees a new line of symmetry now that the shape has been rotated. Rotating the shape will help students see multiple lines because often students just see the lines that run up and down.
 * If students find multiple lines of symmetry, discuss this as a class. For every shape on the page, also, have pre-measured construction paper shapes prepared that you can physically fold in half. The example will be helpful for students to see whether the halves are in fact equal. Encourage students to use different colored pencils for each line they find. (model this with different colored markers)

5. Extension:
 * Have students complete “Symmetry In the Alphabet” worksheet
 * The “Regular Polygons” worksheet showed students that a line of symmetry doesn’t always have to be vertical. Students will be challenged with the “Symmetry In the Alphabet” because they need to think critically. Letters of the alphabet are not simple shapes; they are not all symmetrical and do not all have vertical lines of symmetry. If students understand how to draw a line of symmetry to show whether a shape is symmetrical or not, they will be able to find the symmetry of the alphabet.
 * Homework/Further Extension: Symmetry in the Alphabet worksheet

6. Closure
 * Now that you have learned how to identify a figure as symmetrical or non-symmetrical, what figures have you seen in nature or around the classroom that are symmetrical or non-symmetrical?