First was a chunk of our bread dough -- flour, salt, water, and yeast, having risen overnight:
Then a bit of dry yeast, which wasn't particularly exciting:
I thought that if we dyed our samples with iodine, they might pop a bit more. The bread dough turned out to be pretty tough to do -- it didn't seem that the iodine really penetrated the mix terribly much. Around the periphery, though, we did get an interesting result -- we all thought it looked very much like a top-down view of a forest:
His microscope isn't setup for taking pictures, so unfortunately the quality isn't great.