A physicist and engineer were roommates in college. One night a fire broke out in their apartment. The engineer woke up first and saw the fire. He rem embered the fire extinguisher in every unit, grabbed it and pulled the pin, as instructed, and sprayed the fire with the sodium bicarbonate contained within.
Incredibly, the next night, the exact same fire sprung up in their apartmen t. The physicist was the first to wake up this time. He saw the fire, saw t he fire extinguisher, then went back to bed happy knowing there was a solut ion to the problem.