Or sometimes it's a crazy pedal which can do all sorts of sh*t with harmonies, as well as simulating the sound of a whammy bar (also known as a tremolo bar or, mor accurately, a vibrato bar). Listen to Eruption by Van Halen, or the Star Spangled Banner by Jimi Hendrix for two of the most famous examples of people who wildly attack their guitar's vibrato bar.
Feel free to ignore my ranting.

Member of the Self-Taught Club.

A recent study shows that 8% of teenagers listen to nothing but music with guitars in it. Put this in your sig if you're one of the 92% who isn't a close-minded moron.
there is no such thing as a stupid question

wait after reading your question i take that back, thats such a dumb question

lol haha jk

its a bar that is attached to the bridge that can drastically losen or tighten the strings (depending on where you push down on the bar front or back) to give you a dive bomb affect ( if you listen to ax7 in the song bat country he does that when he gets into the solos and drastically lowered the pitch), or you can losen/tighten the strings alittle just to give a little affect when soloing or just playing some riffs, keep in mind it it just a tool to give you some cool effects when playing, it shouldnt be entirely based on the whammy bar when playing, btw if you are considering getting a whammy bar guitar you might want to get a floyde rose bridge because if you dont it can make the guitar go out of tune really fast when doing so.
but hey
dont feel embarssed or anything when asking a question around here, we were all n00bs once and didnt know what a whammy bar was, so feel free to ask any question you would like and i will try to help you anwser them the best i can
Last edited by the_man101 at Aug 15, 2006,
Another fine example is the song pipeline by the late great SRV using the whammy and an effective technicque known as trills, he creates an amazing sound almost similiar to 2 instroments playing at once.

- songbird