Question

What do scientist use to identify an unknown substance
I say heat it up

Answer 1

Personally, I think this is a ridiculous question. If I'm given an unknown I want to analyze it. You can look at it, heat it, cool it, cut it, melt it, etc and you may have a pretty good idea about what it MIGHT be but it is likely that none of these will be definitive.

Answer 2

Do not necessarily taste it.

Answer 3

Tasting an unknown is never a recommended tool. Smelling an unknown, too, has it's hazards and one must use caution. Back in my younger days I took a real snoot full; once it just about knocked me out. That's why I omitted both of those from my post.