Activities at Home

Line of Symmetry

Look around the house and you will find symmetry all around you, even when you look in the mirror!

What You Need:

  • Ruler, yardstick, or other “straight edge”
  • Household items that are symmetrical
  • Mirror

What You and Your Child Will Do:

  1. Tell your child to pretend that the ruler is an invisible line of symmetry that shows how something can be divided into two congruent parts—parts that are exactly the same size and shape.
  2. Look around the house for items that have symmetry, like a ball, a box of cereal, or even the TV set.
  3. Challenge your child to place the “line of symmetry” up against an item in some way to show that the item has symmetry. If the child places the ruler correctly, confirm that the line of symmetry divides that item into two congruent parts. If the child does not place the ruler correctly, or if the item does not have symmetry, ask, “Does your line of symmetry divide this into two parts that are the same size and shape? Why not?”
  4. Have your child look in the mirror with one eye closed. Hold the ruler on the mirror, level with the child's face. Ask the child to tell you when the line looks like it is at the middle of his or her nose. (Slide the ruler to the left or right, if necessary, until the child says that it is at the middle.)
  5. Talk about how our faces have symmetry, with one eye, one cheek, and one ear on each side of the line. (Also, a line of symmetry divides each nose and each mouth into two congruent parts.)