Symmetry

Purpose:  As a result of this activity, students will be able to understand symmetry. 
Related Standard & Benchmarks:  Mathematics   Standard 5.  Understands and applies basic and advanced properties of the concepts of geometry     Level II [Grade 35]     Benchmark 2. Understands basic properties of figures (e.g., two or threedimensionality, symmetry, number of faces, type of angle) 


Student Product:  The symmetrical mirror image of a shape or design. A written explanation of what symmetry means. 
Material & Resources:  Paper with a design, shape, or picture on it and mirrors 
Teacher's Note:  Small mirrors can be found in science catalogs in the optics section. The junior high or high school science teachers may already have a supply of mirrors that you could use. You can also go to a glass company and ask them to cut small 3 X 5 inch mirrors out of scraps. They can smooth and round the edges and you could back them with duct tape for safety. 
Activity 
Provide students with interesting designs, shapes, or pictures on paper or from a magazine. Faces will work well for this project. Place the mirror perpendicular to the picture, students can observe that the reflection in the mirror is symmetrical to the part of the picture in front of the mirror. The line of symmetry is where the mirror and paper meet. By moving the mirror around to find different lines of symmetry the design changes. The student could write down an explanation or draw a picture of how the mirror always produces a symmetrical image. From their observations the students should be able to describe what symmetry means. 