VO Rotor on second series of Apple Watch

Hello,
I'm trying to figure out whether the S2 watch has a rotor, but I hear nothing when I move my fingers on the screen. Of course, I'm just on the home screen and trying to do this on the smallish face of the watch. I think mine's the 45mm screen or something like that/it's the bigger one, my friend says. Of course, this is the person who gave me the watch as stated here before.