The blue bit is a 9v battery connector. I've had a few plug-in clocks with 9V backup that would beep from time to time when the AC went out.
Indeed, and I figure that the battery might of been removed to shut it up, and not replaced.
Because when you make a working clock out of spare parts, and someone asks you what it is, apparently you're supposed to tell them something else.
Paraphrasing what I said elsewhere, because we KNOW cops do this:
"Hey kid, you were intending to make a bomb with this, weren't you?"
"Tell us how you were planning on showing off this fake bomb to your friends"
"You wanted to scare the faculty with this, didn't you?"
"Common, you can tell us, you admit that you made this to be a fake bomb and you can go home"
etc...
Also - Ron, condemning the kid because his father's supposedly liberal because he's Muslim? Not really good. You have a point how this could be classical school administration over-reaction, independent of any anti-muslim feelings.