62 SEP TEMBER 2022 • WORLD AQUACULTURE • WWW.WA S .ORG throughout the project-based unit, similar to a real-world engineer. A third major objective of the unit was to create a scientific community of practice through which they worked and investigated interactions within the aquaponics system. The curriculum incorporated collaborative learning through roles (i.e., rotating jobs); each member delivered different information to provide a comprehensive view of the environment under study. Students learned the relationship between the parameter change at different scales and the carrying capacity of the system based on evidence (i.e., claim, evidence and reasoning). The curriculum also developed students’ basic applied scientific knowledge commonly associated with aquaculture research. The students’ tasks to investigate interactions within their closed aquaponics systems included: 1) investigate growth performance of fish and plants, 2) monitor the nitrogen cycle, 3) analyze and interpret quantitative data, 4) compare relationships among interdependent factors in ecosystems (i.e., ecological relationships) and 5) use mathematic representations to support and revise explanations based on evidence about factors affecting populations in ecosystems at different scales. In the case of the latter, the purpose was to find the average, identify the trends, utilize graphical comparisons of multiple sets of data gathered from each participating school and acquire STEM-related skills to make graphs and charts from these investigative experiences. Student-Designed Investigations There were two investigation models in the project that offered teachers opportunities to get their students involved in collaborative, inquiry-based group activities in the classroom that align to the major questions. First, there was an 8-week investigation as the classroommodel to anchor the benchmark lessons, develop student knowledge and skills needed to conduct their own investigations, and make connections to the main questions. Second, the 4-week model was the student-driven investigation portion of the project. This model was essentially mini-models to the larger whole-class aquaponics ecosystem whereby student participants designed their own small group experiments (Fig. 2). Both were designed to engage students in active investigation (e.g., research-engagements) as they learned by applying science and engineering practices as they gathered and analyzed data, shared and supported conclusions. Students, while working in small groups, came up with their own investigative questions (e.g., student-driven investigation portion of the project) that related to carrying capacity. Students developed questions early on during their classroommodel investigation while working in small groups. Milestones were incorporated by the teacher to provide students with feedback on research design, data collection/ analysis methods and initial findings concerning their miniresearch projects. The researcher stayed in communication and provided support to each participating teacher regarding student investigations. After students completed their research, the learning unit concluded with a final presentation by students to their peers, teachers, school administrators and researchers. Likewise, their parents and community members were invited to this culminating event. The final group presentations allowed students to share their learned expertise, activities and anchoring events, and communicate the results of the experiments conducted during the unit and bring closure to the project. Evaluation of Outcomes An assessment was conducted to evaluate the effects of the 10-wk aquaponics project-based learning unit and measure changes in students’ understanding of carrying capacity and the nitrification process and their knowledge of ecosystems and related ecological relationships. The study also examined the effects of the learning unit on participating high school students’ attitudes toward STEM in general, and aquaculture and aquaponics in particular, and interests in future STEM-related disciplines and/or STEM career pathways. The hands-on PBI curriculum contributed to students’ content understanding of ecological relationships and concepts. After taking the pre- and post-content-aligned assessment, improvement in the control group of students (Group 1) was significantly lower than that of the treatment groups that were part of the PBI learning (Groups 2, 3 and 4) (Fig. 3). The curriculum contributed to treatment group students’ positive attitudes toward STEM in general and aquaculture and aquaponics in particular (Figs. 4 and 5). Overall, the curriculum improved high school student attitudes FIGURE 3. Means of difference (improvement) scores across all four groups (includes control). FIGURE 4. Pre- and post-intervention survey instrument comparison with respect to the three treatment groups (N = 55).
RkJQdWJsaXNoZXIy MjExNDY=