This lesson is intended to give students a real-life example of why understanding matter is important and works towards developing understanding of MS-PS1-4. I want students to make connections between what they're learning about molecular expansion and contraction and apply it to real-life engineering challenges. Yesterday students researched expansion joints and why they exist. I would like students to delve deeper because that will lead to deeper, more meaningful learning outcomes.
Thermal expansion is covered at the end of the American Chemical Society (ACS) Molecules in Motion 1.2 as an EXPAND section (5E model), but I wanted to take advantage of the opportunity to have my kids investigate thermal expansion joints and model how they work at the molecular level.
I developed this group/partner project to last 2 days and ask my students to:
After you have researched the topic, you and your group will find an example of an thermal expansion joint in another place other than a bridge or sidewalk.
You will then discuss the location of these expansion joints and why they are located there. I really want you to discuss the science behind the expansion joints and would like you to:
Discuss the importance of the expansion joint(s) and what would happen if they weren't used
State what type of data scientists and engineers would need, and how they would acquire it, before building expansion joints for their project.
Model--by drawing detailed pictures of molecules--why the expansion joints are a critical part of any large building, bridge or pipe system. Use circles to represent molecules in your drawings. Then describe the scientific reasons, supported with evidence about why you chose to draw the molecules like this (Use your KLEWS chart and notes from the past few lessons). Try to gain as much insight into the specific construction of the expansion joint and what makes it special to that particular place. As students are creating their model, they are developing crucial abilities to model their understanding (SEP 2). In addition, students are developing arguments and using evidence to support them (SEP 7).
You can make a Google document or short Google presentation. You can create your models using Google Draw and then copy and paste them into your document.
Here is a link to grading rubric.
Students have 2 days to complete the project with their partner. They will research their topic and then apply their understanding of molecular motion to the functioning and rationale for expansion joints.
This is an example of student work and this video discusses the project in more detail.