As part of the unit on human anatomy, Christina Nawas' 7th grade science students (remember them?) came to the lab for a weeklong activity for building model body joints. In preparation for this activity, we spent some quality laser-cutting time making simple cardboard pieces to serve as the foundation pieces, aka "bones."
Students were paired up to first decide and then do research on the specific body joint they want to model. Then it's time to put their clay-modeling skills to the test! Using quick-drying modeling clay, they made everything from "ball and socket" joints to hinge joints.
Once the basic joint structures were in place and dried, the students were next tasked with adding on cartilage, ligaments, tendons, and muscles. We laid out a variety of items - bubble wrap, cotton balls, stretchy athletic tape, bandages, string - and asked them to consider the properties of each material and whether it would be a good model for the particular component they are adding. For example, many groups decided that bubble wrap was a good substance for modeling cartilage while other groups preferred cotton balls. There is no "correct" answer of course; rather, we were more interested in how the students thought about and justified their choices.
The final part of the project was to use motors driven by an Arduino board in order to control the two opposing muscles (which we asked them to model using strings) and simulate the movement of the body joint. Thanks to a piece of software being developed by a group in Spain called Scratch4Arduino (or S4A), the girls got to use a programming language they're familiar with (Scratch) to control the Arduino board. Like with the microscope project, we filmed a short instructional video to show the girls how to set everything up.
After putting everything together and resolving a few technical issues (e.g. how to keep the string from slipping off the motor wheel), every group got to see their movable joints in action!
Check out the video below for a few examples: