An essential sound effect in horror movies, a squeaky door is just an annoyance for most of us that wakes a baby or sets off a round of dog barking. The squeak is most likely caused by metal rubbing ...

The slow squeak of a door hinge at 1 a.m. or the screech of a subway train taking a sharp turn may send a shiver down your spine, but why do these noises happen? Why does metal squeak? It turns out, ...