Is this normal yeast behavior?

http://www.youtube.com/watch?v=70fuB2fZPU0

Can someone give a scientific explanation of why this yeast is popping like that? I never saw that happen in my brews.

Yes, it’s normal. I’ve always assumed it has something to do with yeast/solids shooting up from the yeast cake in conjunction with bursts of CO2 gas release.

While I’ve never really paid much attention, I believe I’ve observed these bursts mainly when fermentation is winding down after yeast has begun to floc. If you watch during the most active phase, the whole carboy is quite turbulent. Again, I’ve never really paid attention, but it might also occur more or less based on flocculation properties of a given yeast strain–occurring more with “clumpy” (e.g., 1968, WLP002) yeast than “powdery” yeast (e.g., 1056, WLP001).

That’s a great video/music! Every time I watch my beer ferment, I’ll have that in my head!

Mine was doing that same thing. I made a video and never uploaded it.
The beer turned out great though.
It never did it with any of my beers until I brewed a wheat beer, Im sure it has something to do with the type of yeast.