To elaborate on bongo's post, "tremolo" means changes in volume and "vibrato" means changes in pitch. Whammy bars do not change volume, they only change pitch.
Most older gibsons that had a whammy bar (see,I didn't use either word and so cleverly avoided getting into a semantic pissing contest)were Bigsbys.
It was huge,cast iron with springs that looked like they came off a small motorcycle.The sound is well known.Think any Neal Young solo.Neal should pay royalties to Bigsby (or vice-versa,I'm not sure).