What do I do if I want to turn off everything that can make my iPhone 4S make noise?

I want to bring my cell phone into class with me, but last time I did that it started playing music and my friends Siri started working. I just want to bring it in class and not have to worry about having it start making noise and me getting ISS. Please* don't put down that I shouldn't be bringing my phone to class because I really have to. Anyway I want to know all the things I need to turn off in order for it not to make any noise at all.

You can turn the phone off, that will stop it from making any noise.