OpenSciEd Unit 8.1 · Lesson 12 · 12.B
Test cushioning materials
From Teacher Edition
Facilitation guidance from the lesson plan — what to notice in student thinking and how to respond while teaching.
Building towards
12.B Construct a model to explain how the changes in the structures of cushioning materials contribute to their function (a reduction in peak forces) at a microscopic level during a collision.
What to look / listen for
- Bubble wrap and cotton balls have a large amount of empty space or air in them and relatively small amounts of solid material across the space they take up.
- Bubble wrap and cotton balls deform easily when a small force is applied.
- Connecting structure to function, identifying a connection to reduction in peak force: e.g., less force between the cushioner and the objects it is in contact with is due to increased space, ability to deform, less-solid material, more-flexible material, and so forth.
Possible student idea
Students may bring up particle-level connections, e.g., these materials are ones that would also exhibit less energy transfer through conduction (from prior units the [unit:wc] and [unit:th]), which may be related to less peak force in a collision.
What to do
If students are not showing the deformation of materials on How can materials reduce peak force on the objects they protect?, have students use their fingers to apply a contact force to the bubble wrap or cotton ball and observe the surface of the bubble wrap and cotton ball. Ask students what the bubble wrap or cotton ball is doing: Is it breaking or is it doing something else when a contact force is applied?
At this point, students have not learned about the deformation differences between solids and gases, but this could be inferred by some students based upon prior learning in the Storms Unit, Bath Bombs Unit, and Cup Design Unit. Some students may be able to show the air becoming more dense upon impact in the bubble wrap or the air moving out of the cotton ball. Since this is a new use of this key concept, ask students to do their best. They will learn more about this in Lessons 13-14. There is no need for intervention on this concept until the end of Lesson 14.
Collect How can materials reduce peak force on the objects they protect? at the end of class. Look for varying differences and explanations in the ways the protective material might be reducing peak forces. These varying ideas can be utilized to motivate student learning in Lessons 13-14. Ask students to throw away their bubble wrap as they leave class. Depending on the type of bubble wrap material, some types of bubble wrap can also be recycled.
Additional Lesson 12 Teacher Guidance
SUPPORTING STUDENTS IN MAKING CONNECTIONS IN ELA
CCSS.ELA-LITERACY.W.8.1
Write arguments to support claims with clear reasons and relevant evidence.
CCSS.ELA-LITERACY.W.8.1.B
Support claim(s) with logical reasoning and relevant evidence, using accurate, credible sources and demonstrating an understanding of the topic or text.