3rd batch, and I'm concerned....

I brewed my 3rd batch of beer last Saturday and everything seems to be going well as far as the fermentation goes EXCEPT this one thing. There are chunks of white stuff floating up and down in the fermenter. I don't think the other 2 did this and they turned out pretty good from what I can tell at this point. These chunks are up to like 1/4" square and they seem to sink, then surface like they are swimming around. Is this normal yeast activity or is this batch contaminated?

FWIW, this is a Mirror Pond clone recipe that I got from my LHBS that is just steeping malt, 6 Lbs of golden LME, and 2.5 Oz of Cascade. The OG was 1.044 and I haven't checked it since it went in the primary...

Like I said.. .I didn't notice it in the other 2 (Porter, and Brown Ale) but maybe that's because they were both way darker.

It's normal. Just sit and enjoy it. Kinda like a lava lamp, eh?

That's just the yeast doin' it's thing. Nothing to worry about.

That's what I thouht,.... BUT it's the BIG chunks that concerned me....

Those yeast are having a big party! What do you do at a big party? Well, hang out with your buddies, of course. Yeast are a lot like people, only they actually treat ya good when you treat them good..... Some people could learn a lot from yeast....