We started simple. We sampled leaves and considered when they turn green. We reflected on the way a tree is similar to and different from a human body. We sampled the classroom. And then we swabbed the classroom for bacteria. The students chose where to swab. The teacher, Mrs. B., was swabbed (belly button, shoe, etc…), the floor too, as were a backpack, the soil outside, a flagpole outside, a flagpole inside (flagpoles seem to be a conspicuous feature of the elementary school day), the computer table, a lunch box and a trashcan. I was also swabbed. The students then generated hypotheses about where we might find the most kinds of bacteria. This bacterial work was not yet science; it was outreach—showing the students’ results that exemplify what we already know—but in this context we could still walk through the steps of science. We could generate hypotheses and consider them in light of what we found.
The students hypothesized that they would find the most kinds of bacteria in trashcans and in the soil. This was the hypothesis about which we found the most consensus.
Students also, of course, hypothesized many other whimsical and less whimsical things. This being elementary school, those hypotheses included statements that had nothing whatsoever to do with bacteria, or biology, or anything anyone had talked about that day, hypotheses, in other words, of the “One time I went to New Jersey” variety. Trips to New Jersey were acknowledged and then we moved on.
Dr. Mary Jane Epps and Dr. De Anna Beasley worked with Dr. Julie Urban at the Museum of Natural Sciences in Raleigh, North Carolina, to grow the microbes found on the swabs from the classroom. The microbes were grown on standard microbe food, which is to say what grew was not everything that lived in the classroom but instead just those things that eat the most ordinary of foods. Our work in houses suggests that in the classroom we would expect thousands of species of bacteria to be living. The cultures we used would grow, perhaps, a few dozen of those thousands; they were a sample of the big story in the way that a bucket full of fish is a sample of the sea.
Nonetheless, the culture plates, which you can see below, did seem to suggest that trashcan and soil samples were relatively more diverse (as was the carpet). We talked about this in class. A key take home from our discussion was the idea, taken for granted by microbiologists, but novel to most kids (and adults) that most of the bacteria around us every day are either beneficial or innocuous, that if you removed all of the bacteria from the classroom or a human body that it would be bad (perhaps deadly) and that the goal, in washing hands, is to wash away the species that have most recently arrived, those species that have not yet ensconced themselves.
One of the points I wanted to make with the class was when they wash their hands, they benefit both themselves and others (in the same way that they do so if they are vaccinated). As a model of this idea we had the students pass a shell (as a model of a bad bacteria species) across the classroom several times. Each time the shell was passed, we randomly designated a larger number of kids as hand washers, hand washers who could not pass the shell. We then graphed the rate at which the shell moved as a function of the number of hand washers. Happily the graph showed that as the number of hand washers increased, the shell-bacteria moved more slowly (we also learned that if enough kids have washed their hands in this experiment that the shell will actually stop moving across the classroom, but that this is so frustrating to the students that one of the students will pretend not to be a hand washer just to help the shell-bacteria along).
In talking about hand washing, the kids asked all kinds of questions about what eats the microbes on their bodies (bacteriophages), what bacteria eat, bacteria in space, and how one sees bacteria. And then the discussion (in as much as one can have a discussion with 100 eight-year-old kids all of whom have their hand up and are wiggling so much to be seen that they are bumping other kids the way that molecules in boiling water bump into each other right before the boil) turned to the question of what the kids should wash their hands with.
The kids all wanted to know. The teachers did, too (especially after seeing the picture of what grew on the teacher shoe). In response I said what I always say, that anti-microbial wipes aren’t any better than soap and water and that there is a fair amount of evidence that the bacteria-killing ingredient in anti-microbial wipes (triclosan) does some bad things, such as turning boy fish into girl fish (at which several boys were so alarmed as to hear anything else I said). I then noted that no one had ever really studied what microbes can be found on anti-microbial wipes, versus alcohol wipes versus soap or how exactly each of those products (and the microbes on them) affect the microbes on skin. Soap is covered in microbes; the same is almost inevitably true of alcohol wipes and triclosan wipes too. This is something I say a lot. I give enough talks that I suspect I literally say it once a week and in all of the times that I have said it, no group of adults has even done what the kids did.
The kids asked if we could do the study. They asked if we could compare the soap and the wipes. YES! Yes, kids, we can. Yes, teachers, we can. And so we are starting the Fred A. Olds study of the microbes that live on soap, triclosan wipes and alcohol wipes. Next week in class we will begin to discuss the design of the experiment (bring your notebooks, kids). We will then take swabs of the different cleaning agents (in accord with however the students decide to do the study) and then culture and sequence the swabs at the Museum of Natural Sciences in downtown Raleigh. As we do, I’ll post the on-goings of the study here. Our aim is to do real science here and to publish this work. After all, if no one has ever done this, we ought to do it right.
And so when you go home tonight and wash with whatever you wash with, you should wonder what it is you are spreading on your skin, what it is fostering and what it is killing. We really don’t know, at least not yet. The first people who do know, if we do everything right, will be a hundred eager kids.