Unit 1 Reflections: Seed Germination Lab

I feel unit 1 has taken an excessive amount of time.  I would have liked to have been done with unit 1 by the end of last week.. instead, we'll be testing this Wednesday.  But oh my gosh, did this lab reveal some misconceptions, especially with my brightest honors class...

In this lab, students were design an experiment to test the effect of an environmental condition (light, pH, water availability, temperature, etc.) on seed germination.  After reading the teacher notes, for some reason I got it in my head that it would be good to run this experiment over the course of a week.  I had no idea how long it would take for the seeds to germinate in "altered" conditions, and I wanted to make sure we got data.  (During the week while this experiment was running, we kept busy.  We did the Simpsons Controls and Variables WS, took a quiz, read "The Blind Man and the Elephant" poem, learned about the procedures for writing lab reports, and reviewed graphing skills.  My honors classes also learned about histograms.)  FYI, A week was completely unnecessary.  Two or three days would have been sufficient for observations.

One of the problems with extending this experiment over a week is that some of the seeds went beyond just germination and actually became sizable sprouts:

Clearly beyond germination

This threw the students for a bit of a loop, as they lost track of what their planned dependent variable was supposed to be (# of seeds germinated) and started focusing on how much the plants grew, if they lived or died after germinating, if they developed roots and leaves, etc.  Now... I encouraged my students to record their observations when they counted the number of seeds germinated, but I did not put out any rulers for the students to measure growth.  A few of my honors students had rulers in their notebooks and did it themselves, but no group asked me personally for a ruler.  But MANY groups in both standard and honors biology tried to estimate and graph growth after the fact when they presented their results, and used growth to support/refute their initial hypothesis.  This lead to a really good discussion on bias and what data you can/should use to form your conclusion.

I also had one group of honors students who set up too small of sample sizes (1 seed in each experimental group) and had 100% germination in all of their samples.  Since their quantitative data was all the same, they tried to graph their qualitative observations instead. I caught them designing a numerical "ranking" system based on their qualitative observations that made my head spin.  Another good discussion on bias and how it's perfectly okay to have inconclusive results from an experiment.

And then I had another group of (honors) students decide to focus their conclusion on the "best" seed from each of their experimental groups and control.  They based their entire verbal, graphical, diagrammatic white board on each of the "best" seeds, even though this group in particular had created the largest sample sizes out of any of my classes.  Talk about MY mind being blown-- here was a group who I really thought "got it" based on their experimental design, yet had MUCH to learn about how to interpret data.

I only snapped pictures of a handful of white boards in a single class today-- the others I forgot about.  Even looking at these pictures now, I keep noticing more potential misconceptions that I may have missed in class.  For example, I initially thought the board below was pretty decent:  yet I didn't even question their choice of the word "faster."  Nor did I catch how they labeled their days on the graph in the class discussion.

After our board meeting, each group was to create a "mind map" (improved model) for experimental design.  Of course, time was running out about this point, and while we created a consensus "mind map" pulling from the groups' white boards, it was a  more teacher-led than I would have liked it to be.

An example of a standard bio class' improved "model"

The amount of time all of this took today was excessive.  However, the students were really on task and having great discussion among their groups about their results.  I was impressed.  But at the same time, we have a ton of material to cover before the end of course exam.  We can't be spending this much time on everything.

During the board meetings, I'm now hitting a problem where the same few students are the only ones chiming in during what is intended to be "class discussion."  I have some ideas on how to (force myself to) remedy this for the next unit.  But right now, since I feel like my questioning skills are still so shaky, I'm thrilled when anyone answers a question.  I had quite a number of questions fall flat today.

Also... remember that "bright" honors class so riddled with misconceptions?  They were possibly the saddest, most dejected looking group of students I've ever seen after I called out group after group for making the same mistakes with bias.  I must have been unintentionally brusque with my delivery.  While I tried to build them back up after the fact, I'm afraid they came away from this activity discouraged.  Definitely something to keep in mind for the future.