How big is Snap! in UC Berkeley? I just didn't see any mentions of it on the website. Does it make sense to mention Snap! knowledge when applying to UC Berkeley or they will look at me like on a kid 
We use it in teaching our CS course for non-majors (CS 10, Beauty and Joy of Computing), which is taken by something like 1K students every semester, so I think that's pretty significant. However, nobody outside of CS knows about it, including the Admissions people. So you should treat it as you would any obscure expertise, i.e., if you're going to talk about it, explain what it is. ("Snap! is a visual language, like Scratch, but way more advanced." Actually I'm not sure they'll know about Scratch either, unless you get a reader with school-age kids. :~) So write it yourself. It's fine to say "It's the language used in CS 10 at Berkeley.") I don't think they'll know enough to say "oh isn't that that kid language?" :~)
thanks i ll research about that after getting my SATs in spring.