I’ve been busily rubbing all sorts of things on bacterial growth plates after all the great suggestions I got yesterday. I want to present the data from the first big experiment suggested by JerryM, who wondered what kind of bacteria would be present on my hands immediately after washing them and then every thirty minutes after that until the next washing. My hypothesis was that there would be a small number of colonies on the plate I touched right after washing, and then steadily growing in number over time. I thought this would especially be true considering that I spend most of my time touching bacteria and silkworms anyway, and yesterday I was also spending a lot of time touching dirty things on purpose to plate them for the experiment.
Well, boy was I wrong:
And here is the graph of the same data. Surprisingly the highest number of colonies wasn’t after two hours of not washing, but only after 30 minutes. Even more surprising, the smallest number of colonies wasn’t right after washing, but at the end of the experiment after two hours!
This result is totally fascinating, and I think warrants more investigation. How does the ecosystem of bacteria on the skin change over time? How do harsh soaps affect this ecosystem? Does the skin ecology naturally maintain a lower number of the bacteria that can form colonies on LB plates and washing throws it off? Or is this result just a total fluke? Stay tuned for more experiments, and keep the suggestions coming!