This lesson continues the Cells 'R Us project based learning experience. 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:
This photosynthesis and cell respiration mini-unit uses the Web-based Inquiry Science Environment (WISE) developed by UC Berkeley. Before attempting to access the interactive with the students, the teacher must have created an account, and started a run of the "Photosynthesis and Cell Respiration" project. Here's how:
Just in case you missed it, the ID number for the Photosynthesis and Cell Respiration project in WISE is 9932.
Here is a walkthrough of the student account creation process:
At this level, most students have been exposed to the concept of photosynthesis. In order to uncover the depth of what they know, as well as to engage the students, I have them write "all they know about photosynthesis" in a chain-note.
The chain-note starts with one student writing the title, "What we know about photosynthesis" on a piece of binder paper and writing a response in a complete sentence. When done, the paper is then passed from student-to-student within a table, with each student adding an idea in a complete sentence. I tell them to read the previous responses because they should not write down the same thing as another student.
Once the chain-note reaches the initial student, I tell the students to keep it until the end of class. (They will be adding to it and turn it in at the end of class.)
I like using chain-notes to get students back into an idea we have already discussed because it gives them a sense of what they already know and sets the stage for what is to come. I also use chain notes when I'm introducing a new concept to elicit prior knowledge, or after a lesson for a quick assessment.
Once we are all thinking about photosynthesis, I present the video, "Where do trees get their mass from?" made by Veritasium, a science video blog featuring experiments, and more.
I pause at several points throughout the video to elicit student's responses:
0:28: I ask the students to chime in with their own response to the initial question (Where do trees get their mass from?).
1:17: How did Von Helmont eliminate soil as a source of nourishment for plants?
3:37: What does the narrator mean when he states that "trees are mostly made out of air"?
End: What were the ingredients mentioned throughout the video as necessary for plants to grow (increase in mass)?
Stopping the video several times to allow for class discussion is a key strategy that allows students to stop and think about the information. I have found that if you run a video without pausing, students tend to enter a "passive watch" mode, and don't think they are accountable for any of the information being presented.
Once we conclude, I tell the students that we will continue our study of this process through a series of interactives and visualizations on a site called WISE.
For the WISE run, I assign partnerships based on the clock buddies the students created at the beginning of the year. I randomly pick a number, and tell students that this will be their partner for this WISE activity.
As the students are working on the visualizations, I am walking around the classroom checking in on student understanding through the conversations I overhear.
Remember the chain-note from the beginning of the lesson? This is where it comes into play again, as I tell the students that each table must now read through it, discuss their original ideas and "star" or highlight any that might have changed because of what they now know. Finally, each partnership must add one more sentence to it, and turn it in.
Note to teachers: This is not a graded deliverable. I look through them in search of misconceptions that need to be addressed. This same paper is given back to the students on the next day, where they will go through the same process at the end of class.