Balsa Wood Bridge Construction


Provide a hands-on, construction-oriented class project that encourages creativity and gives students practical experience with bridge design and construction. Students will be designing and creating bridges using balsa wood sections. Emphasis should be placed on the creation of sturdy structures while considering environmental conscious building practices with efficient use of resources. Author: Joseph Sanford, Pitsco, Junior ACE, North State Building Industry Foundation, 2011.

Expected Student Outcomes/Objectives

The students will design a bridge that crosses a theoretical river of 10"-12" wide. Some students may be able to build bridges that are longer while still able to withstand the minimum weight. While designing and building their bridges, students will learn about effective building strategies.

Description of Activities

This project involves careful use of resources above all else, to introduce the concept of good stewardship and efficient design, defined as the bridge design which can hold the most weightusing the least materials. This lesson is recommended for smaller class settings, but you can break larger classes into smaller groups just as well. This project allows you to provide hands-on instruction for individual students or groups of students as they construct the bridges. Discuss with the students the strategies of simple, effective construction techniques. Discuss budgeting of resources, green building practices (especially how to plan the cuts to minimize waste), and situations where renewable resources may be substitutes for traditional resources. Students should also observe that reduced overhead does not necessarily equate to reduced quality of products.

Culminating Activity and/or Assessment

Towards the end of the final session, the instructor holds a "weigh-in ceremony" in front of the students, where the capacity of each bridge is measured. Expect some well-built bridges to actually explode when they break, meaning they fail all at once under incredible tension. Then the instructor will hold a ceremony after all bridges are finished with the testing. Give a prize to the overall winner or have categories, such as best looking design, longest bridge, strongest bridge, etc. and give prizes for each.

Instructional Materials Needed

Pitsco Balsa Bridge Kits, “structural shapes and forces” manuals, green wood glue, sandpaper, timber cutters, Exacto knives, foam core boards, wax paper, straight pins, pliers, cardboard, 5-gallon bucket, water pitcher, weight gauge, paper, prizes (optional)

Instructional Materials Provided

discussion topics, preparation instructions

Additional criteria

Cost: The instructor will have to acquire PitsCo bridge building kits, or make their own, and will need the necessary tools and supplies.

Curriculum type: Lesson

Academic subject areas: Laboratory Science; Career-Technical Education

States' Career Clusters: Science, Technology, Engineering & Math; Architecture & Construction

California Industry sector(s): Manufacturing and Product Development; Engineering and Architecture; Building and Construction Trades

Duration: 2-3 Classroom Hours

Grade Target: Middle/Junior High

Level of Expertise for CTE: Introductory

Standards Addressed: Alignment with Common Core, NGSS, C3 or CTE Standards evident

Keywords: Bridge, construction, teamwork, structure, shapes, design, efficiency, resources, budget

Source: Organization/Publisher-developed

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