Academic journal article The Science Teacher

Exploring Osmosis & Diffusion in Cells: A Guided-Inquiry Activity for Biology Classes, Developed through the Lesson-Study Process in Cells

Academic journal article The Science Teacher

Exploring Osmosis & Diffusion in Cells: A Guided-Inquiry Activity for Biology Classes, Developed through the Lesson-Study Process in Cells

Article excerpt

Guided inquiry is an instructional technique that requires students to answer a teacher-proposed research question, design an investigation, collect and analyze data, and then develop a conclusion (Bell, Smetana, and Binns 2005; NRC 2000). The idea is for students to learn how to draw a conclusion based on data they collect and analyze. As part of the process, they also learn about the content under investigation.

In this article, we describe a guided-inquiry lesson developed through the lesson-study process (Fernandez 2002; Lewis 2002). This lesson helps students understand the concepts of diffusion and osmosis as they relate to cell function (Content Standard C; NRC 1996, p. 181) and develop the abilities necessary to conduct scientific inquiry (Content Standard A; NRC 1996, p. 173).

Developing the lesson

We developed this lesson as part of a lesson study, a professional development activity in which teachers work together to collaboratively create a meaningful and effective lesson (Fernandez 2002; Lewis 2002). During the process, teachers learn more about the teaching and learning of certain content. A lesson study involves planning, teaching, observing, analyzing, and refining a lesson over several iterative cycles. Figure 1 (p. 56) illustrates the various components of a single lesson-study cycle (Lewis, Perry, and Hurd 2004).

To provide focus and direction for our work, we first selected an overarching goal (to help students understand diffusion and osmosis as they relate to cell function) and a related research question to explore ("What essential elements, in terms of design and delivery, of an inquiry-based lesson must be in place to foster student understanding of diffusion and osmosis?"). This research question then served to guide our work during the lesson-study process (see "Organizing a lesson study," p. 60, for more information).

After determining our goal and research focus, we developed the first iteration of our lesson. The original idea came from an investigation described in Exploring the Living World (Lawson 1995). In this lesson, students are asked to develop a way to test the validity or acceptability of two alternative hypotheses that can be used to explain why red blood cells appear to shrink when immersed in salt water.


One teacher from our group taught the first version of the lesson we developed in a high school biology class while the rest of us observed and collected information about students' interactions and questions. We also recorded the lesson to help identify potential barriers to student learning. We then came together as a group to watch the video, discuss our observations, and analyze samples of student work to ensure that students reached our learning targets.

Next, we revised the lesson based on our observations. Our goal at this stage was to improve the overall impact and delivery. We looked to the videos and student work samples for misconceptions and common errors in experimental design that we could explicitly address during the second iteration of the lesson.

Then, once we made the necessary changes, a second member of our group implemented the second version of the lesson in a different classroom--while the rest of us again observed and collected data. Students in both classes had little or no experience with inquiry-based instruction, and both classes had similar student demographics (i.e., 9th- and 10th-grade students, of which 80% were European American, 20% were African American, 40% were female, and 15% received free or reduced lunch).

We then came together again for a final discussion and revision of the lesson. In the following paragraphs, we describe this final iteration of the lesson, some strategies for enacting this type of lesson, and what we learned about student learning as a result of this process.

The guided-inquiry lesson

To begin the lesson, students are shown two videos--both of which are available on YouTube (see "On the web"). …

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