One way of describing symbols is they are constants whose value is their
name.

As far as your example is concerned, the two options give you rather the
same effect. Most likely "water" is held as an object of type string
whereas :water is held as an entry in a symbol table. Quite possibly one
is more efficient that the other (either faster or taking less space)
but Ruby is not supposed to be a language that worries about such things
(it's supposed to be human oriented), and I'm not convinced you could
rely on that in all implementations.

-- 
Posted via http://www.ruby-forum.com/.