In our last Great Experiments class, we read about Pasteur’s broth experiment and thought a little about how we might recreate it. Today, I set up the supplies I had for them and let them take the lead on setting things up, making choices, and actually doing the work. They worked through the various gas nozzles not working, how to get the bunsen burner set up and how much broth to use.
Oh yeah, we should use some safety equipment.
That’s better. While the broth was boiling, we started a new reading related to spontaneous generation. They were supposed to keep some paper handy and record all of the questions they had as they made their way through the article.
Since we had two sets of broth, they decided to boil the first for 10 minutes and the second for 30 minutes. About 15 minutes in, though, one of the students looked up from the reading and noticed that we had boiled off a lot of the broth and that one flask was coated in something brown.
“What is that brown stuff?” Great question. I left it unanswered for now. We can think more about it in our next class (on Tuesday).
We took care of the flasks and turned everything off, then we took a little time to discuss the reading. First, we talked in small groups; I went around and checked in with each table. Then, we had a larger discussion as a class. I’m still not great at structuring these (yet), so there were awkward parts. I’m glad I have some time to think about how I want to focus our next day together.