“There’s got to be a way to use the toothpicks!”
“What are we supposed to do with the notecards?”
These are some of the responses I overheard during our problem-based lesson. Last time (part 1), the students learned about some of the components to tissues (cells and fibers), and I’m happy to report that most of the classes remembered that fibers were an important component. Last Friday (part 2), the students were given a problem to solve. We talked about how in my field we make something called a scaffold to support cellular growth, and the scaffold is often desired to have similar mechanical properties to the tissue we’re designing. Most of the kids already understood the word scaffold, but in a different context (scaffolds to build buildings), so I used that context to help explain scaffolds in my field. The students’ problem was to design a large scale model of a bone scaffold that met some requirements that they as a class set. I had them tell me what some of the goals for this scaffold would be and we ended up with two main goals: 1) The scaffold must be strong/sturdy and 2) The scaffold has to have room for cells.
They worked in groups of two and each group was given a limited set of materials to build with (e.g. popsicle sticks, toothpicks, notecards, tape, paper, etc.) and they could choose which materials they wanted to use. As an engineer, just having a goal for the scaffold to be strong is quite unsatisfactory, however, I didn’t think giving a lesson on mechanics of materials was really necessary because the overall goal of the mechanical properties came across. One group came up to me and told me they were finished so I took a look at their construct.
Me: “What would happen if I put a little bit of weight on this construct, for example this light textbook?”
Student: “It would collapse.”
Me: “If it’s going to collapse with just a small amount of weight added to it, would you feel comfortable putting that in your bone?”
Overall, this activity seemed very challenging to them and I originally did not think it would be. Part of the problem was the groups would look at what another group had and automatically assume that they should be doing the same thing. There were over 10 groups in each class and most of their scaffolds looked identical and as a result, most were very “unsturdy.” There were a few groups that went away from the norm though and had some very unique and more successful designs.
This Friday, they will be finishing up their scaffolds and sharing their designs with the rest of the class. We’ll observe and discuss what worked, what didn’t work, and I’m also hoping to get across the fact that there isn’t a “right” answer.
Final Part 3 – coming soon!