Demonstrate symmetry for the kids with the shapes. Hold up a shape and show them that the shape has two identical halves if you draw a line down the center, either horizontally or vertically. Demonstrate the line of symmetry on the octagon, pentagon, circle, triangle, star, square and rectangle by drawing it with a ruler and marker.
Demonstrate an unsymmetrical line with the triangle by drawing a line across the triangle to create two unequal parts. Demonstrate an unsymmetrical line with the circle by drawing a line across the circle to divide it in a one-third piece and a two-thirds piece.
Show children symmetry on symmetrical pictures of objects like a book, a glass, a rug and a window. Draw lines through the book and the glass from top to bottom, through a rug with a symmetrical pattern and shape and through a window. Draw lines either vertically or horizontally.
Illustrate unsymmetrical objects by showing children pictures of objects like a vase of flowers, a toy and a car. Show kids how no matter where you draw a line on these objects, there will not be two equal mirror images.
Look for lines of symmetry both indoors and outdoors on objects. Encourage students to make a list of objects with lines of symmetry and objects that are not symmetrical. Examples of symmetrical objects include a butterfly, a flower and a leaf. Examples of unsymmetrical objects include a tree and a number six.