Building a Stronger (Sweeter) New Orleans
Students create and analyze composite materials with the intent of using the materials to construct a structure with optimal strength and minimal density. The composite materials are made of puffed rice cereal, marshmallows and chocolate chips. Teams vary the concentrations of the three components to create their composite materials. They determine the material density and test its compressive strength by placing weights on it and measuring how much the material compresses. Students graph stress vs. strain and determine Young's modulus to analyze the strength of their materials.
This composite material is also a sweet treat.Copyright 2015 Sarah Wigodsky, School of Engineering, NYU Polytechnic
Students play the role of composite material engineers as they create the best (lightest, yet sturdiest) composite material to be used in an area that suffers from severe ground subsidence, such as New Orleans.
Material engineers choose constituents (that is, ingredients) for composites based on their density and rigidity. Engineers design new materials and perform compression tests on them to determine their strength. Engineers analyze stress vs. strain graphs to find Young's modulus, thereby determining the material stiffness. Based on the material's strength and the extent of its elastic region, composite engineers determine what materials would be optimal for a given application.
After this activity, students should be able to:
- Design a strong, yet lightweight, composite material.
- Construct and analyze a stress vs. strain graph for a composite material.
- Compare different composite materials and explain which is the most desirable building material, considering strength and density.