For this round of PBL, I decided to let my students become engineers, designing a household device to remove excess carbon dioxide from the air. Why? In the name of teaching the connections between photosynthesis and cell respiration. I want students to apply their knowledge of these two processes, not just repeat back what they know. Unfortunately, that happened too many times in their last set of PBL presentations. They listed the cause of the little girl's death they were trying to solve, then they separately listed all sorts of science about membrane transport....they knew and owned the knowledge of membrane transport in their own words, but it seemed they could not use it to explain the cause of the little girl's death. The limited attempts that I saw were very general in nature ("The little girl died of rotenone poisoning, which meant she wasn't making ATP, and all of her symptoms were because she wasn't making ATP"). My students obviously need more practice at being able to use and apply the science knowledge they have come to own; however, those types of thinking skills don't just happen overnight. And they don't just happen with one PBL unit--which is why I have a few more planned.
But back to my student engineers.
I introduced the problem using this clip from the movie Apollo 13. We then went through the steps you see on this page of my class website, developing our problem statements, forming our know/need to know list, doing independent research and filling in the class research summary, asking questions, answering them, and asking more questions. As a matter of fact, what impressed me the most about this foray into PBL is that my students were asking me many more questions than I was asking them--which secretly delighted me, but did not delight my students when I wondered aloud if there were a wonderful tool on the internet where they could type in words and get back a list of links to web pages ; a place that, perhaps, begins with the letter "G" and ends with "oogle." I also tried to link the learning back to our ecology unit and link it forward to the cell respiration and photosynthesis goodness they would be studying.
But that's what I'm finding tough to do with PBL--making sure they have the base knowledge (the Level 4 understanding, in my standards-based scoring terminology) of cell respiration and photosynthesis they need in order to use/apply that knowledge without me doing any up-front knowledge dispensation. I have come to find out that the crafting of the original problem is crucial--that it must be designed so that students really do need to know the science in order to successfully provide a viable solution. After the problem has been designed with this in mind, the next step is providing students with the opportunities to acquire that knowledge and work with it so they can truly own it.
This is where Juno comes in. I've written before about how it can be used to create your own online textbook, and that's what I've continued to do with it. However, since I've been shifting towards doing more and more PBL units, it has become instrumental in having students come to a Level 4 understanding of the science concepts. What I do is write a reading (aligned to the I can statements for the unit) where students, at certain intervals in the reading, answer questions I write specifically to help them get to a level 4. And, after grading their last set of progress checks, it seems to be working. What's so exciting about this is that I never talked at length about any photosynthesis or cell respiration concepts. I looked at the answers to their questions from the reading (which are nicely organized in Juno for me) in order to see where the stumblings and misunderstandings where, and those became the focus of my daily journal questions. Students and I would discuss these questions, revise their understandings by revising their answers to their Juno questions, and then the PBL learning goodness would continue. It seems to have paid off, because, looking at their last set of progress checks (my new name for tests), they are doing fabulously. Do some of them still need to fix their knowledge? Absolutely; and that's what we will be doing after we return from break.
But what really struck me during this PBL unit is how much my students never cease to amaze me. They don't realize it, but they learned all on their own the basics of what is traditionally pretty tough stuff for early high schoolers (because it is so steeped in scary biochemistry and it cannot be concretely modeled for them before their very eyes). My job was just to provide the setup and support for learning rather than the learning itself. When I used to teach photosynthesis and cellular respiration in the traditional way, all I got were a lot of blank looks, gratuitous head nods to my "Does everybody get it?" questions so I would just move along, and too many "I have no idea" answers on my quizzes and tests.
But now, with me out of the way of their learning, they can truly be amazing learners in their own right--because I suspect they are realizing they can do more on their own than they thought they could. I can see them slowly building their own confidence in their own abilities, something that has been stripped from them in the past. They have been traditionally been disempowered to do their own learning, relying on the teacher's understanding of concepts rather than creating their own. But not with PBL. PBL allows them to construct their own knowledge, build their own meanings--making the knowledge and the process of learning theirs, not someone else's. Is this happening for all students? Nope. I still have some young people that are refusing to be as amazing as they could be, but that's alright--I can't expect every student to accept what is for them a drastic shift in how school is done. But you had better believe I am going to keep trying to make them see that they have to do the learning; if I do it for them, the learning will never be owned by them.
The other PBL skill I need to keep trying to master is having students apply the knowledge of the science concepts to the solution of the problem. For my next PBL Unit (which is going to be about DNA & protein synthesis), I think I will need to include more of those application questions in the Juno activities that I write (what I call Level 5 questions). These questions could be about their problem (interpreting an electrophoresis gel at issue in a court trial), or they could just be ACT-type questions where they are given new information and must use what they have learned about DNA and protein synthesis in order to answer the question. In either case, I will have to closely monitor their answers as they progress through the Juno activities, and focus their daily questions on the thinking issues that arise when they are working on those Level 5 questions.
I'm still no expert at PBL. Even though I still don't feel like I'm doing it completely "right," I know that by getting outside of my comfort zone and jumping into this with both feet is still doing right by my students. Don't let the fear of how different PBL is from the educational norm stop you from trying it--you'll see how good it is for your students and for your own growth as a professional.