A U.S. Army-funded research project at the University of Illinois has developed a material that changes color when it is met with force or becomes overstressed. Among the examples trotted out in this month's issue of Nature are an elastomer that starts out the color of amber and turns progressively more orange as it's pulled, eventually turning red as it reaches its point of failure and snaps (see the photo on the right). Once relieved of stress, the material reverts to its original color -- and it can be used multiple times. Suggested uses for this technology include parachute cords, climbing ropes, coatings for bridges -- anything, really, that you'd want a heads-up on before imminent failure. Pretty wild, huh? [
