Termites and Experimental Design

This week both of my classes (high school level Biology and AP Biology) did a termite lab.  I love both of these labs. In general, I'm not a big fan of bugs.  Dissecting grasshoppers grosses me out. But termites--I just tell myself they're little white ants. Fortunately, you are supposed to avoid touching the termites, so we use paintbrushes to move them around. No complaints here about that! They're pretty low maintenance too. I order a 25 pack of worker termites from Carolina. Both years I've ordered them, Carolina has been generous with the termites, and we've had at least 40 in the package.

In HS level Biology our termite lab is part of our evolution unit. This lab emphasizes the adaptations of the termites and how that helps them to live to reproduce--increasing their fitness for their environment.  But to me, the real emphasis of this lab (and AP Bio's) is experimental design. For my middle school/high schoolers this lab provides a whole lab period of design/evaluate/redesign.

Each lab group starts with a petri dish with a piece of paper that I've instructed them to draw a closed shape on with a Paper-mate red pen.  I give them three termites and have them observe for a few minutes. Then they must decide on a hypothesis about why the termites behave the way they do and test it.  Before they test the hypothesis, they write out the independent and independent variables and the controls they will use so they are only testing one variable at a time.  Then students carry out the experiment and observe.  After observing for a few minutes, more questions arise and a new or updated hypothesis is formed.  The process repeats. Our goal is at least 4 hypotheses tested.

Each time they go through the process, they start to see how their design can be improved. We can talk about how scientists in real life are continually working to improve the design of their experiments and fine tune their hypotheses.  The process gets them thinking in a different way than cook book experiments do.  For many labs, this process just takes too long, but this one goes fast enough and is simple enough to refine several times in one period.

In AP Biology, this is our animal behavior lab.  In this lab, we also discuss taxis and kinesis. We start the same way as the other lab, with the petri dishes, but then they have to develop a hypothesis to test using the choice chambers.  They also have to perform a chi-square analysis for each set of results to determine if random chance brought the termites to the chambers that they went to, or if some other factor was in play. We had some great discussion about experimental design with one group who was testing different colors of pen.  After their first trial, they realized that maybe the shapes were too far away from each other for the termites to even realized there was another side.  Their second round included drawing the shapes closer together. They improved on their experimental design.

The source of the idea for this lab came from the book, Biology Inquiries: Standards-Based Labs, Assessments, and Discussion Lessons by Martin Shields.  I developed a sheet that I give my HS Biology kids and then I also outlined requirements for a lab report for my AP Bio kids. I'll include both below.

Termites Trails Mystery Lab for Biology

Animal Behavior Lab for AP Biology

First Day of School Plans

For my AP Biology class, the students already know each other, I just don't know them.  We don't need any sort of mixer, so we get right to work.  I want them to get practice designing an experiment and get them comfortable with using google sheets. We use google sheets for nearly all our labs, because it allows for instant sharing of everyone's data.  

Since I want to focus on learning how to set up a lab and use sheets, I present them with a simple question to investigate.  We delve into the heavy AP labs soon enough.  I got this simple idea from a lab from Cooking with Science on Teachers Pay Teachers and combined it with an exercise from Biology Inquiries: Standards-Based Labs, Assessments, and Discussion Lessons by Martin Shields. The question to investigate is, "Do you get more juice out of lemons if you heat them first?" After designing the experiment and collecting data, they work on finding the standard deviation and graph the data including 2 Standard Error of the Mean. We could also add in a chi-square analysis, but I think they have enough on their plates already.

For the Living Environment class, we use stations as a get to know your classmates, get set up for class, and practice some lab techniques. The inspiration for this activity was from Amy Brown Science and her Science Chat. My students get their textbook, set up their notebook, adjust their goggles and lab aprons, and pick their preferred size of gloves. They also practice reading the meniscus in a graduated cylinder, using a ruler, using pH paper, and calibrating our digital scales. To try to save paper, I give them an answer sheet to fill in as they go that is a half sheet (but is quite tight on space). Here is a link to the stations I use and the link to the answer sheets for the students to use and keep track of what stations they still need to go to.