. >>> in a columbia university lecture hall, professor james valentini begins his chemistry lecture wheny breaks out into song. ♪ when we come to class it seems we've all lost asleep ♪ >> and it's all caught on camera. ♪ but when did we become this way, so disillusioned, so blase ♪ ♪ i can make the calculation ♪ >> a lot of people liked that video because we all want that to happen. disrupting the ordinary day. people love musicals and hate math and science. everybody wants to see that happen in the lecture. but, again, i have terrible skepticism. i'm a bitter, bitter person who watches this and says where's the lap mike. why is there so many cameras. why is the sound quality so good in this lecture hall? ♪ you must think we only party and drink beer ♪ >> the professor i thought would step in at some point. >> could a couple of students hold up a huge class right before the final without anyone stopping them? many believe the professor and the students were in on it. but others say the reactions seem too genuine. ♪ reach, teach ♪ >> so was the video real or was it fake? >> people have as