Answer:
unlike traditional guitars theres ones where they have springs inside the guitar and a special kind of whammy bar which floats making it pull up and push down making the sound of the strings go lower or higher.
pros and cons time, lets start with pros
all kinds of cool effects you can do with them.
a better sounding guitar to many
stays in tune longer in experience if its locked properly
easier to adjust action
cons
strings break quicker if you use the whammy a lot
can go out of tune faster if you use the whammy a lot
if its set up in say E tuning you can only play in E otherwise the gutiar will seem broken
setups to different string gauges and tunings can be expensive
if you want one its best to get a guitar with it installed in it already and if you use classifieds sites because you can get them pretty cheap online but be sure is to ask as many questions as you want as that's how I bought my first two guitars