Activity:

Have students explore lines of symmetry of familiar shapes with mirrors or Miras and through paper folding. Give each student a paper square. Direct the students to fold the square in half, open the papers, and point to the fold lines. Tell the students, “Another name for the fold line is the line of symmetry. One side of the line is a copy (or mirror image) of what is on the other side of the line.” To help the students verify your explanation, place a mirror or Mira on each student’s fold line, and have the student check if one side is a mirror image of the other side. Have them use crayons to color their fold lines. Encourage students to find other lines of symmetry on their squares, and have them use a crayon of a different color for each line.6

Teacher Notes:

“Teachers should guide students to recognize, describe, and informally prove the symmetric characteristics of designs through the materials they [teachers] supply and the questions they ask. Students can use pattern blocks to create designs with line and rotational symmetry or use paper cutouts, paper folding, and mirrors to investigate lines of symmetry.” 7