Students build a bridge by ordering the bars from the smallest to the tallest. They show symmetry by creating the same order on the opposite side.
Students describe other situations where size order occurs.
Collect pictures of bridges to share with the students. Ask students to describe what they know about bridges. Using the pictures, identify the sequence of the beams above the bridges. Discuss the order of the beams and the lines of symmetry. Ask each child or pairs of children to build a bridge.