In this video excerpt from NOVA’s "Making Stuff: Stronger", host and New York Times technology columnist David Pogue visits DuPont™, where Kevlar® was invented. After learning how this bulletproof material is made, David puts its strength to the test with an ice pick. A related demonstration tests and compares the tensile strength and elasticity of Kevlar®, nylon, steel, and cotton thread by using them to lift weighted buckets. Students learn that materials can be strong in different ways—some have high tensile strength, others are more elastic—and that materials scientists test the strength of materials by stressing them to their breaking point.
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