Suspension Bridges: Connecting Lives
Students plan, build, and test their own suspension bridges.
- Grades: 6–8
- Unit Plan:
Students will use a hands-on approach to abstract concepts of geometric shapes and measurement. Students will compare the connection of the foundation and strength of Ruby Bridges to the foundation and strength of a suspension bridge.
- Research suspension bridges
- Demonstrate knowledge of abstract concepts of geometric shapes and measurement
- Design a suspension bridge
- Construct a suspension bridge
- Describe the process
- Create a presentation
- Chart paper
- Wax paper
- Hot glue
- *White glue/Wood glue
- *Round toothpicks (1 box)
- Build A Bridge Project (PDF)
*Students could furnish these materials from home, due to the cost of materials
Set Up and Prepare
- Become familiar with suspension bridges. These books and websites will help the students with their designs:
Built to Last: Building America's Amazing Bridges, Dams, Tunnels, and Skyscrapers by George Sullivan
Suspension Bridge from Wikipedia, the free encyclopedia
Bridges Are to Cross by Philemon Sturges
- Reserve the library for research. Have students use other sources along with the Internet to research about suspension bridges, e.g. encyclopedia, books about bridges, etc.
- Design a suspension bridge on chart paper (according to criteria on PDF) for students to understand the expectations of the project.
- Construct a suspension bridge (according to criteria on PDF) to model to students at the beginning of the lesson.
- Make copies of the Build a Bridge Project (PDF) for each of the students.
Day 1: Introduction
Step 1: Display the design and replica bridge that you have created for students to visualize the expectations.
Step 2: Introduce the project to the class by asking the students, "What are some of the purposes for bridges?" "Is the foundation and structure important?" In your class discussion, you can bring out the relationship between metaphorical bridges (between people, nations, etc.) and actual bridges.
Step 3: Distribute the Build A Bridge Project (PDF). Encourage students by telling them that they are going to become amateur architects, and then guide students through the timeline, criteria, and grading scale.
Step 4: Proceed to the library or resource room to research suspension bridges. (Have some websites available for students who are having difficulty.)
Step 5: Encourage students to find a suspension bridge that they would be interested in building and if at all possible print or copy an example of the bridge. If printer or copier is not available, have the students sketch a rough blueprint to use when designing their bridge.
Step 6: Once all the students have a suspension design in mind, explain to them that tomorrow they will be designing their suspension bridge.
Day 2: Planning and Design
Step 1: Review with the students the criteria for the design of bridge. They must use chart paper, ruler and pencil, and the design must have a full-scale model with measurements labeled and a half-scale model with measurements labeled.
Step 2: Walk around the room to ensure students understand the expectations and are on task.
Day 3: Construct Bridge
|The Foundation and Strength|
Step 1: Review with the students the criteria for the construction of the suspension bridge.
Step 2: Distribute the building materials. Explain to the students that the twine represents the cable, toothpicks the steel and glue the welding of the suspension bridge. They will be constructing the major parts of the bridge and when all of the glue is dry, you will hot glue the major pieces together.
Step 3: Give each student enough wax paper to cover his or her work area, to keep the glue off the desk or table.
Step 4: Encourage students to use their chart paper design as a reference.
Step 5: Walk about the room to ensure that students understand that there is a timeline that must be met and to make sure that students are on task.
Day 4: Construct Bridge, continued
Step 1: Continue monitoring students to ensure completion of bridge.
Step 2: For fast finishers, start hot gluing the student's suspension bridge. The hot glue is only for connecting the major pieces, e.g. sides of the bridge to the roadway and the pillars to the roadway, not to construct the major pieces.
Day 5: Complete Bridge
Step 1: Hot glue all major pieces of the student's suspension bridge.
Step 2: Review criteria for presentation and descriptive paper.
Step 3: Students finalize the project by writing their one-page description of the process of building a suspension bridge.
Step 4: Students get prepared for tomorrow's presentations.
Day 6: Presentation
Step 1: Students present their final suspension bridge. Encourage students to explain their reasoning for choosing their bridge design, what their measurements are, how many toothpicks they used, predict how many textbooks their bridge will withstand in the test of strength contest, and so on.
Step 2: For the "Test of Strength Contest," have students place their bridges on a flat surface. Place consistently weighted items (copies of the same book, for example) on the bridge, one by one, until the bridge collapses or turns over depending on your criteria for the test of strength.
- To more clearly link this lesson to your earlier reading, have the students brainstorm character traits that can lead to amazing successes, as in the Ruby Bridges story.
- Have them represent each chosen attribute by labeling parts of their bridges.
Invite parents/guardians to the presentation and the test of strength contest.
- Connecting Ruby Bridges and suspension bridges.
- Research suspension bridges.
- Design a suspension bridge.
- Construct a suspension bridge.
- Present and participate in the test of strength contest.
- Did the student's use their time wisely?
- Did the student's understand the connection with Ruby Bridges and the building of the suspension bridge?
- Was there enough time?
- Was the instruction clear enough for the students?
- Did the example of the design and bridge help the students?
- Assessed by staying on task, used time wisely, and neatness.
- Assessed by the grading scale for the design, bridge, presentation and paper.