## Symmetry in Nature

### Kenneth BlackmanSanta Rosa District Schools

#### Description

The students use a variety of observation and measurement techniques to identify lines of symmetry and also use graphing techniques to determine plots of ordered pairs.

#### Objectives

The student use the properties of parallelism, perpendicularity, and symmetry in solving real-world problems.

#### Materials

- Graphing Paper
- Crayons
- Rulers (one for each student)
- Magnolia Leaves (one for each student)
- Pencil

#### Preparations

1. Pick the Magnolia Leaves.
2. Make sure all needed materials are placed in the classroom.
3. Put the definitions of key words on the board.
A. Line symmetry
B. Ordered Pair
C. X Axis
D. Y Axis
E. Origin

#### Procedures

1. Introduce the concept of graphing and line symmetry. Ask students to brainstorm how we can know if something is symmetrical. Ask how we can determine symmetry from a graph. Place several ordered pairs on the board. Model to the students how to plot an ordered pair on a graph. Have the students practice graphing and plotting points using examples on the board. Ask students to note symmetrical ordered pairs.

2. Hand out the magnolia leaves and have the students make imprints on the graphing paper using the crayons. Have the students lay the leaf stem on the Y axis.

3. Discuss the concept of line symmetry. Discuss what happens to an ordered pair of opposite points. Demonstrate how this shows symmetry.

4. Have the students plot several points along the margin or edge of the leaf imprint. Have the students observe what happens to the plotted points as you move past the line of symmetry.

5. Have the students switch leaves and make another graph showing the line of symmetry and plotted points.

6. Review with the students the concept of line symmetry and graphing.

7. At the bottom of their graphs, ask students to answer the brainstormed question in #1: How can we know if something is symmetrical and can it be determined from a graph?

#### Assessments

NOTE: This lesson only addresses symmetry.
The students will be assessed by teacher observation and the review of the graphs and written answer.Graphs will be assessed for correct placing of the line of symmetry, labeling, and plotting of ordered pairs. The written answer should indicate characteristics of symmetry.