During the cell unit of Advanced Placement biology, students are required to do three investigations (labs): Diffusion and Osmosis, Photosynthesis, and Cellular Respiration. Students work in groups of 3 to 4 to work through these investigations and analyze data. I often have them only turn in ONE copy of the lab guide because as a group, they should have reached the same conclusions. Unfortunately, many students interpret this to mean that only one person needs to do the lab. It became apparent in the last exam that a few of the students did not engage in the analysis with their groups and could not answer questions that were intended to evaluate their understanding of concepts in the lab.
For example, this question from the test:
A solution is contained within a semipermeable membrane, a dialysis tube. The solution has an unknown concentration of sucrose. Describe an experiment that you could perform to get an estimate of the solution’s molarity. (You may use more than one dialysis tube with the unknown.)
Students should have been able to draw upon the knowledge gained in the lab and describe placing the unknown tube into solutions of sucrose to see if it gains or loses water, pointing the the molarity of the unknown. I was disheartened to discover that a large section of my students did not know the answer and when I asked them specifically why they had trouble with the question, their answer was “it wasn’t my job to write the answers down.” Clearly, I needed to make some changes with how students are engaging in group activities and investigations.
The next unit is evolution and while there aren’t as many laboratory investigations, there are case studies and other group activities that will require students to collaborate effectively. I will be employing new strategies to improve how students interact with each other on these cases.
1. Peer evaluations – Normally I have a participation grade for each unit, in this one, students will be asked to evaluate each other using a specific rubric that asks them to grade each other. Though I will have the final say in their participation grade, I’m hoping that students will make a greater effort to participate knowing that team members can have an impact on their final grade.
2. Paper Roulette – I learned this strategy from an English teacher. For group projects, each member of the group answers all of the questions and does the analysis. When it’s time to turn the paper in, each member places the papers face down on the table and mixes them up. The teacher chooses one from the pile to grade. This will also encourage members of the team to check each other’s work.
3. Individual Participation Rubric – This is the rubric I use for their class participation grade, based upon my observations of their engagement throughout the unit. They receive 4 grades throughout the semester.
One of the issues with grading work for case studies is that much of the learning is informal, as students discuss scenarios and analyze charts. The answers that they eventually write down are sometimes not as important as the processes employed to get the answer. I circulate around the class, sit an talk with each group and try to engage them with critical questions. A peer evaluation for this process might actually be preferable to grading specific questions and answers on the page. The problem is, without the paper form questions, students lose focus and don’t stay on task.
Most of the case studies I use come from The National Center for Case Study Teaching in Science.