**Designing bridges**

**Objective:** To allow students to compare and order integer bars by length, and to investigate symmetry.

**Manipulative Activity:** 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.

Distribute integer (Cuisenaire) bars to all the children in the class. Ask each child or pairs of children to build a bridge.

- What bars were used?
- Where is the line of symmetry?
- How are the bars ordered?

**Technology Activity:** Students use an integer bar applet written by Jacobo Bulaevsky to reinforce ordering by size. Depending on the availability of computers for your students, this activity can be done individually, with partners, in groups, or as a class.

Refer to How to Use the Integer Bar Program for directions.

Have students go to Designing Bridges.

**Paper/Pencil Activity:** Depending on the level of your students, you can have them complete this activity individually or with assistance. Here are some possible activities:

- Students draw pictures of their bridges
- Students record the number (quantity) and colours of bars used
- Students research and write about the types and uses of bridges. Here are some links to resources on bridges that might be useful.

**Literature Connection:**

*Bridges*

Ken Robbins, (New York: Dial Books, 1991)

*Bridges Are to Cross*

Philemon Sturges, Giles Laroche (Illustrator), Joy Peskin (Editor), (New York: Puffin, 2000)

*Bridges Connect: A Building Block Book (Building Block Books)*

Lee Sullivan Hill, (Minneapolis: Carolrhoda Books, 1996)