In and Out of Cells - Conclude your Own
Lesson 13 of 18
Objective: Students will be able to explain how solutes and other materials move across membranes.
The Cell Processes unit is part 2 of my Cells 'R Us project based learning experience. Once the students are familiar with the structure of cells, we move on to how cells work. The lessons in this sequence are based on the "need to know's" created by the students (with guidance) for the Cells 'R Us project.
The complete sequence I use for the Cells 'R Us project is:
Students usually do not need much in order to engage in this lesson since they are coming in curious to see what happened to "their" eggs. To take advantage of this, I ask the students to do a quick write of the similarities/differences between osmosis and diffusion. This can be done as a Venn diagram, but they have to have one statement in each section.
I tell the students that they will now move on to the lab report portion of the Design your Own experiment activity, and once again review the expectations and rubric. Once we are in agreement, I hand out Says-Mean-Matters half-sheets, and take out their experiments. I use the says-means- matters strategy in this lesson to support the students in making observations and allow them to differentiate between observations, analysis and conclusions.
As students are working I am walking around the room making sure the groups are engaged productively in formulating evidence based on data and examining their own understanding (NGSS Practice 7), engaging in discussions with peers (NGSS Practice 8) using the talking moves they have been taught, and evaluating the validity of the findings of others. These discussions lead into having the students draft their final lab report, which they submit through Edmodo (SW1, SW2,SW3, SW4). Although I will only review one report per team, it is imperative that all students participate, so when I visit with each team, I interview the different teammates asking for their own evidence based conclusions, do a quick check of their says-means-matters half sheets and the use of scientific vocabulary.
Although having them experiment "on their own" can seem daunting, the growth while discussing the results and examining their understanding in light of new evidence (SP7) are evident:
As students turn in their work, I direct them to meet with their Cells 'R Us teams and discuss how they will use what they have learned in their final project.
Note to teachers: Active transport is discussed only briefly during these lessons since I only want them to be able to understand that passive transport does not require energy, while active transport does. At the middle school level, the NGSS only requires that the students understand how organelles contribute to the function of a cell, and reserves cell transport for the high school level.
To bring this lesson to a close, I ask for student volunteers to share any new wonderings they have based on their results. This is done as a quick whip-around and I encourage students to perform experiments based on these wonderings on their own.