Operation Build a Bridge and Get Over It
Students act as structural engineers and learn about forces and load distributions as they follow the steps of the engineering design process to design and build small-scale bridges using wooden tongue depressors and glue. Teams brainstorm ideas that meet the size and material design constraints and create prototype bridges of the most promising solutions. They test their bridges to see how much weight they can hold until they break and then determine which have the highest strength-to-weight ratios. They examine the prototype failures to identify future improvements. This activity is part of a unit in which multiple activities are brought together for an all-day school/multi-school concluding “engineering field day” competition.
Tower Bridge in Sacramento, CA.Copyright 2006 Michael Grindstaff, Wikimedia Commons http://commons.wikimedia.org/wiki/File:Tower_Bridge_Sacramento_edit.jpg
Structural engineering is one of the oldest engineering disciplines. Through this classic introduction to engineering activity, students gain an understanding of some of the challenges faced by engineers whose designs must protect public safety, such as bridges like the Golden Gate Bridge that thousands of people depend upon every day. Students experience the engineering design process to achieve effective designs, creating and testing prototype bridges to failure. They also experience the use of scale models in engineering to study how the forces and loads acting on bridges (or any structures) can result in damage. Also like real-world engineers, students analyze their bridge designs by calculating strength-to-weight ratios as a measure of structural efficiency.
After this activity, students should be able to:
- Apply and explain the use of the engineering design process to design a bridge with given size limitations.
- Calculate the strength-to-weight ratio of their final designs.
- Explain how tension and compression forces act on a bridge support when a load is applied.