Summary
This activity was inspired by Prof. Margot Vigeant of Bucknell University.
Special thanks to Cynthia Burke and Chris Bell for helpful discussions about this activity.
Overview
Steel, concrete, wood—real bridges are built from many different materials. How do engineers decide which materials to use? In this activity, your students will expand on the previous paper bridges lesson plan by building and testing bridges made from different materials.
Learning Objectives
- Understand that different materials have different properties.
- Interpret the results of an experiment to determine which material is best suited for a certain purpose.
NGSS Alignment
This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:- 2-PS1-2. Analyze data obtained from testing different materials to determine which materials have the properties that are best suited for an intended purpose.
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Science & Engineering Practices
Planning and Carrying out Investigations. Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence to answer a question.
Planning and Carrying out Investigations. Make observations (firsthand or from media) and/or measurements to collect data that can be used to make comparisons. Engaging in Argument from Evidence. Construct an argument with evidence to support a claim. |
Disciplinary Core Ideas
PS1.A: Structure and Properties of Matter. Different properties are suited to different purposes.
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Crosscutting Concepts
Cause and Effect. Simple tests can be designed to gather evidence to support or refute student ideas about causes.
Influence of Engineering, Technology, and Science, on Society and the Natural World. Every human-made product is designed by applying some knowledge of the natural world and is built using materials derived from the natural world. |
Materials
Construction paper, aluminum foil, wax paper, card stock, small books or boxes, pennies, tape and a ruler.
For each group of students:
- Sheets of printer or construction paper (2)
- Sheets of aluminum foil (2)
- Sheets of wax paper (2)
- Sheets of cardstock or manila folder (2)
- Stack of books, or small boxes (2)
- Pennies (about 30, more may be required for stronger designs)
- Tape
- Ruler
Background Information for Teachers
This section contains a quick review for teachers of the science and concepts covered in this lesson.If you haven't already, read the background section for the first paper bridges lesson plan. In that lesson, students explored how a bridge's shape can affect its strength. In this activity they will explore how a bridge's material affects its strength. What happens if you make the bridge out of aluminum foil, wax paper, or cardstock instead of regular paper (Figure 1)?
Figure 1. The same bridge design made from four different materials.
Different materials have different properties. In this project, we are specifically concerned with the material's mechanical properties (as opposed to other types of properties, like chemical or optical properties). How easy is the material to stretch, squeeze, tear, or bend? If you bend the material slightly, does it bounce back to its original shape, or stay bent? How far can you stretch or bend the material before it breaks? Does it break slowly (like stretching out a ball of clay) or suddenly (like snapping a wooden pencil)? All of these factors determine what materials engineers use to build bridges. For example, if a bridge flexes a little bit under a large amount of weight (like a train), you want it to return to its original shape.
In this project, first your students will explore the mechanical properties of some different materials. They will use their observations to predict which material will make the strongest bridge. Then they will design an experiment to test bridges made from different materials and see which one is the strongest.
