30.1.08

PV = nrT. The expression has nontrivial implications for a Discovery Channel "Smash Lab" where the protagonists attempt to design an air-bag car-catcher to reduce the damage to automobiles in a train-car collision. At this stage of development, the project is unlikely to change the minds of any advocates of complete separation of rail and road traffic. It did clear up one thing, though: the protagonists discovered that a suitably durable material would be embrittled if it was rapidly filled by high-pressure carbon dioxide (as it expands and the pressure drops, the temperature falls.) This does not happen with quick-deploying airplane escape slides, because that design uses valves that exploit the laws of physics in such a way as to introduce air at ambient temperatures, thus further speeding up the inflation of the slide, while keeping the material warm enough to remain supple.

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