On a rerun of "Columbo," I thought that Detective Columbo was investigating whether a gunshot downstairs opened a bedroom door upstairs. Can sound open a door, and how? Also, how can sound break a glass, something which I already knew?

If the door was slightly ajar or not fully latched closed prior to the gunshot, sure, the shot causes the air molecules and door molecules to vibrate, translating into sound when it reaches our ears, and mechanical vibrating pressure waves when hitting the door, which could shake it open. If the door however was latched shut, it is unlikely that the gunshot vibes would be strong enough to open it. As for breaking glass, this might happen when the frequency (pitch) of the sound was the same as the glass's natural frequency, causing the glass to "resonate" by creating high amplitude vibrations in the glass causing failure. The natural frequency of the glass depends on its shape and size and thickness, and support conditions. A wine glass might resonate and break by the sound wave, but it would be most difficult to resonate a window pane by sound, since it is much stiffer. The pane could break, however, by a large noise from say a nearby explosion, this would be by a process similar to the gunshot opening the door, not related to the resonant frequency.

gerry: Your answer sounds correct. I do not see anyone disputing your answer. Thanks.