Lesson plan
Fatigue Failure
Students will investigate fatigue failure in paper clips and design a new paper clip.
Grades 9–12Physics & Physical Science
Overview
Students investigate why materials break by testing fatigue failure in paper clips. The lesson begins with a Do Now question on why objects break and examples from students' own lives. Groups then repeatedly bend a paper clip until it fails, count the complete cycles, and record the class data on the board and a handout. After a video on fatigue failure, students consider how engineers use such tests and what modification would help a paper clip last longer. An optional extension has the class set three criteria and three constraints for a new design. An exit ticket asks what caused the clip to break.
Lesson Objectives
- Investigate fatigue failure in paper clips and design a new paper clip.
Standards
NGSS · 3
- HS-ETS1-2Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
- HS-ETS1-3Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.
- HS-PS2-6Communicate scientific and technical information about why the molecular-level structure is important in the function of design materials.