I'm sorry, I know it's mean, but I sort of laughed when I read this (mainly because the first one was just thrown away, and I just pictured someone looking at it, going "what the hell?" and tossing it in the garbage). The whammy bar, when screwed into the bridge, is used to change string tension. When Eddie Van Halen makes his guitar go bwoooooooooooow really really low, he's using a whammy bar. Suicidalmoose is right in that it can be used to loosen the strings, but it can also tighten and raise pitch. Not only that, but the lowered pitch does not always have to be just a half-step lower. When you depress the whammy bar with control, you can dive as many steps as you want, the strings will continue to loosen.