Jon Mayes
Balsa Wood Bridge
NJ Core Curriculum Content Standards
5.1 Science Practices: Science is both a body of knowledge and an evidence-based, model-building
enterprise that continually extends, refines, and revises knowledge. The four Science Practices
strands encompass the knowledge and reasoning skills that students must acquire to be proficient in
science.
A. Understand Scientific Explanations: Students understand core concepts and principles of
science and use measurement and observation tools to assist in categorizing, representing, and
interpreting the natural and designed world.
B. Generate Scientific Evidence Through Active Investigations: Students master the conceptual,
mathematical, physical, and computational tools that need to be applied when constructing and
evaluating claims.
C. Reflect on Scientific Knowledge: Scientific knowledge builds on itself over time.
D. Participate Productively in Science: The growth of scientific knowledge involves critique and
communication, which are social practices that are governed by a core set of values and norms.
5.2 Physical Science: Physical science principles, including fundamental ideas about matter, energy,
and motion, are powerful conceptual tools for making sense of phenomena in physical, living, and
Earth systems science.
A. Properties of Matter: All objects and substances in the natural world are composed of matter.
Matter has two fundamental properties: matter takes up space, and matter has inertia.
D. Energy Transfer and Conservation: The conservation of energy can be demonstrated by
keeping track of familiar forms of energy as they are transferred from one object to another.
8.2 Technology Education, Engineering, and Design: All students will develop an understanding of
the nature and impact of technology, engineering, technological design, and the designed world, as
they relate to the individual, global society, and the environment.
B. Design: Critical Thinking, Problem Solving, and Decision-Making: The design process is a
systematic approach to solving problems.
Equipment
Balsa wood, exacto knives, wood glue
What Students Should Know Before The Lesson
Students should have a strong background in geometry. They need to also have a rudimentary
knowledge of the structural integrity of certain shapes and the construction of supports and buttresses
on a structure. Lastly, students should be familiar with the engineering design process.
Lesson Objectives, Goals, Important Ideas, and How I Will Assess Them
The objective of this lesson is for students to work collaboratively in the creation of a balsa
wood bridge. This bridge will then have weight added until its structural integrity is compromised. The
procedural goal achieved in doing this is a review, reinforcement, and application of the engineering
process. They must understand the forms of design associated with this project and the types of
engineers who would work on such a project.
They must meta-cognitively reflect on how the science and engineering aspects of such a
project. How are the scientific method and the engineering design process related, and how do they
work together to achieve this desired goal.
Epistemologically, students should be able to reason how and why certain types of engineers
are chosen for such a project, and how the engineers work together to complete the project. Students
should discuss the social impact and importance of engineers and their work on societal values and
solutions to societal problems.
I will formatively assess them by making rounds in the room and asking them questions which
will guide and broaden their thought processes during the activity. Also, I will read and make comments
on their reports so they can read my comments, reflect on them, and revise the report for resubmission.
Potential Student Difficulties
Students may have trouble with completing all aspects of the engineering design process to
design and create a structurally sound bridge. They must draw the design for the bridge before they set
out building it, and develop a method of constructing it which ensures quality of the design and ease.
To help them with this, I will facilitate their cooperation and recollection of how circuits work
with guiding questions. Also, I will scaffold them in their implementation of the engineering design
process in a similar way.
The Lesson
Application Experiment: Balsa Bridge
Equipment: Balsa wood, exacto knives, wood glue
Experiment: Design and build a bridge out of the balsa wood provided. You are only permitted to use
the balsa wood given to you and you may only put wood glue on the joints. Make your design first, then
think about your method of construction. Keep in mind that you have to get to the parts of the bridge
you want to build, and it’s hard to put support structures on the inside of the bridge when you have
already constructed the outside skeleton. When you are done with your bridges we will test their
strength by adding weight to the top of the bridge until it breaks.
Before bell Prep and sit down.
Reading and mentally preparing for Greeting and finishing set up for
the activity.
equipment.
0-5 min
Listening
Explaining and introducing the
activity
Design, build, and test
Walking around monitoring the
students, helping them, and
keeping them motivated.
Listening
Explaining to them what they
must write up in the lab report
for homework.
5-40 min
40-45 min
Activity Intro
Build a solar car
HW
Homework: Create a formal lab report for this experiment. Include the full scientific method for this
type of experiment. Also, include a description of the reason why you chose a given design for your
bridge. Why did you choose certain shapes and structures and how are they superior for supporting
weight. Lastly, discuss the similarities and differences of the engineering design process and the
scientific method, and how did you use both in your design. What kinds of engineers are required for a
project such as this? What kind of social responsibility are these engineers burdened with and how will
their work impact society?
Modifications for Different Learners
This activity incorporates creating, design, building, measuring, analyzing, applying, and
performing so it has a desirable aspect for most types of learners.