Question: Oh, no! The elevator cable snaps and the backup safety system fails and down, down, down you go. How do you optimize your chances of surviving? Would it help to leap up just before the cab collides at the shaft's bottom?

Answer: Better to drop to the floor and spread out, preferably on your back, which is possible now since there is some drag on the cab from the guide rails, says Jearl Walker in "The Flying Circus of Physics." The idea is to spread the force you are about to experience over as much body surface area as possible. Standing is ill advised, since under such a collision your ankles will collapse and your body's trunk will crash hard to the floor. Jumping up at the last moment (surely this is impossible to time from an enclosed cab) may be the worst thing you can try since this will only slow you slightly and "if the cab ricochets from the bottom of the shaft you'll be traveling downward as the floor of the cab is traveling upward, and shortly later ... Well, no need for the gory details."

In a tragic incident on July 28, 1945, a U.S. Army B.-25 bomber crashed into the 78th and 79th floors of the Empire State Building, killing three in the plane and 10 workers inside the building. When an injured elevator operator was being taken down for medical help, the cable snapped and the elevator cab fell to the subbasement. Rescuers found the two women occupants alive though badly injured. The safety devices had apparently slowed their descent sufficiently to diminish the crash.

"There is no report on what the women did during the fall, but because of fear and the jostling, I doubt that they remained standing."

Question: Gold, as you may know, is malleable (can be pounded into sheets), ductile (drawn into wires) and virtually indestructible. In what sense is gold "green" and in what sense is it not? Also, where can most of the metal be found these days as reserves, reservoirs and otherwise?

Answer: Gold is eco-green in that windows in some apartment buildings are coated with it to help reflect sun in the summer and retain heat in the winter, says Lee Aundra Temescuin of Discover magazine. However, getting the metal is far from green since gold mines spew cyanide into waterways and nitrogen and sulfur oxides into the air. "In 2000, a cyanide spill at a Romanian mine made the local water for 2.5 million people undrinkable."