Lab is getting really busy--and satisfying. The goal of the lab is enrichment and isolation: the students start with mud or soil or gutter water, and using selective media and growth conditions that favor certain organisms, they isolate pure cultures of specific types of microbes. A maxim of environmental microbiology states that "Everything is everywhere." That is, you can take any sample, and you can isolate any type from it. So, from the same sample, the students isolate Bacilli, Streptomyces, Purple Bacteria, Cyanobacteria, Prosthecate Bacteria, Fermenters, and so on.
The first five weeks of this are frustrating for the impatient. Stuff has to grow, and many things grow slowly. But now, after seven weeks, we get the payoff: students sit down, twiddle with their microscopes, and spontaneously get up and dance a happy dance. It's the dance of somebody who finally has a beautiful pure culture of Caulobacter: Isn't that just beautiful? More on Caulobacter later.