Using the Composites Module in the High School Chemistry Classroom
About Renee and her class
Renee teaches chemistry at a suburban high school near Chicago . She used the Composites Module with her advanced sophomore chemistry/physics class in the first few weeks of the fall semester. She had taught the Composites Module once before during the previous year and attended a summer workshop on the Materials World Modules prior to her initial use.
The chemistry/physics class met for a double period (93 minutes) and alternated between one day of physics and one day of chemistry. However, due to extenuating circumstances unrelated to MWM, for this particular project, the class met every day for about a week.
The class is one of four accelerated sophomore chemistry/physics classes. In each class, students worked in their regular lab groups of three, which the students had selected at the beginning of the school year.
Renee spent quite a bit of time on the initial activities, in part because she allowed her students to come up with their own testing procedures for several of the activities. In all, she spent two and a half days on the initial activities, and two and a half days on the design project.
Tuesday , Renee introduced the module and had students do the ice composite demo activity and the composite hunt. Towards the end of the period, students cut and glued foam beams that would be used the following day.
Wednesday , students did the strength and stiffness and foam composite activities.
Thursday , Renee ran the optional geometric reinforcement activity, where students explore how the direction of fibers in fiber-reinforced tape affects the strength and stiffness of the foam beams used on Wednesday. Towards the end of the period, Renee introduced the design project, and gave groups about twenty minutes to begin brainstorming ideas.
Friday was the primary design building and testing day. Groups came to class with materials and often shared materials with other groups. Students were also very willing to share their ideas with each other. Students did not make formal presentations of their designs, but did write on the board which of their designs worked or didn't work.
Monday , students had a half-period to build and test their redesigns. (The other half of the period was devoted to physics.) Several students stayed late to finish testing their designs, including one group that produced the best performing design of any in Renee's classes.
After the redesign was complete, students had a few days to document their reflections in their lab journals, which were turned in towards the end of the week.
The group of Ellen, Lisa, and Carrie explored several design ideas, especially during the first day of building (Friday). Through these video clips linked below, you can track their progress as they consider various ideas. (Real Player required)
On Thursday, the group brainstormed some materials, including plastic rods, wires, and clay. Thursday night, Lisa went to Tom Thumb, a local art supply store, to buy some of these materials.
Friday, the group inventoried the materials they had collected overnight, and discussed their design ideas with another group. The first design they built used a plastic rod and wire inside the straw and duct tape around the outside. This design seemed promising, but when the group tested it, they felt it was not flexible enough; the pole bent under a load and did not return to its original shape.
Prior to building their second design, the group considered several alternative materials, including clay. Renee suggested that they see what other groups were using as well.
Their second design used a piece of fiber optic cable in place of some of the wire, which they had determined was at fault in the performance of their first design. Their third design of the day used wood skewers instead of the fiber optic cable. These designs, too, had trouble with the flexibility test, although this was due in part to the group's apparent misunderstanding that the pole had to return to exactly level - actually, it could return to within 1 cm of level. (See the cantilever test for an example of how the students tested their designs.)
Renee used a 25 point rubric to assess her students' performance during the Composites Module. In addition, she offered five extra credit points to the one group out of all four of her classes that produced the best design and two extra credit points to each student in the class that produced the best design.
Many teachers who use the Materials World Modules use extra credit points as a prize for the group that produces the best overall design.
Offering extra credit motivates many students to strive for the best design. However, this increased competition also tends to reduce the amount of communication among groups, because students do not want to give away their "trade secrets." As a result, students do not participate in the exchange of scientific ideas and cannot learn from each other as easily as when the exchange of information is encouraged.
Renee tried to address this issue when she designed her assessment method for the Composites Module. The first year she used the module, she gave extra credit to the group with the best design across all of her classes. She felt that this had resulted in little sharing of ideas and wanted to devise a method to motivate students without stifling communication.
What she did was to offer five extra credit points (the project was worth 25 points total) to the group with the best design in all here classes, but also to promise two extra credit points to everyone in the class from which the best design came. This approach did appear to be successful in getting students within a class to work together and share ideas.
Click here to see a video clip of Renee explains her extra credit scheme (Real Player required).