Breaking Beams
Students learn about stress and strain by designing and building beams using polymer clay. They compete to find the best beam strength to beam weight ratio, and learn about the trade-offs engineers make when designing a structure.
Cracks result when there is excessive stress placed on a beam causing the beam to essentially break.Copyright http://upload.wikimedia.org/wikipedia/en/2/2a/Bridge_deck_-_punching_failure_bottom_cracking.png
Engineers consider the forces of stress and strain in their choice of design and materials. Civil engineers often use a system of beams and columns in their structural design, to keep us safe in our homes and schools. Engineers specify the exact materials from which objects and structures should be made, so that walls support the weight of the roof, airplanes fly safely at high altitude, wheels do not fall off, chairs support the weight of people, bridges support the loads that travel them, shopping carts support groceries, and strollers support children, and so on.
After this activity, students should be able to:
- Recognize various engineered beam designs.
- Identify instances of elastic and plastic deformation.
- Describe the process of how engineers and scientists conduct materials testing to determine the ultimate tensile strength of a beam.
- Perform data collection and analysis (ranking).
The activity setup to stress test student-designed beams.Copyright Chris Yakacki, Integrated Teaching and Learning Laboratory and Program, University of Colorado at Boulder, 2003.