Desert ecosystems such as Arizona's Sonoran Desert are environments that are defined by complex interactions among plants, animals, and people. Understanding natural environments such as these requires that students grasp these interactions, and many teachers believe that bringing students to natural environments on field trips can boost the students' understanding of the ecosystems. This study aimed to explore how a field trip and a family trip to a desert environment affect students' mental models of the ecosystem.
The students in this study were in grades 4 and 7 and learned about the Sonoran Desert. Teachers in the control group received training in using activities provided by the Sonoran Desert Center (SDC) and implemented the activities in the classroom. Teachers in the experimental group used the same activities, and supplemented the activities with two visits to the Sonoran Desert Center, where instruction complemented the in-class activities. During the course of the school year, three of the seventh-grade teachers in the experimental group invited students and parents to Family Science Club activities at the SDC. They organized hands-on activities for students and their families on two Saturdays. Twenty-three students and their families participated.
To assess the students' mental models of the ecosystem, the researcher asked students to draw and explain a desert environment. The researcher asked the students to make a drawing before the experiment and then again several months later after the field trips. Mental models are illustrations of a person's thinking. The author cites previous research that has established this kind of draw-and-explain task as a valid method for understanding students' perceptions and gauging the sophistication of their ideas.
The researcher used a rubric to categorize the drawings as novice or sophisticated and also categorized the drawings into one of four basic mental models:
Model 1: A place where animals/plants live--a natural place;
Model 2: A place that supports life (animal, plant, and human);
Model 3: A place impacted or modified by human activity or intervention; and
Model 4: A place where animals, plants, and humans live.
For the fourth graders, the researcher's analysis did not find that field trips made any difference in the type or sophistication of mental models students depicted. Among seventh graders, there was no difference in sophistication of mental models between students who went on field trips and those who did not. There was a small but significant difference in mental models, though, for seventh graders who went on a field trip. This group shifted slightly away from mental model one (desert as a place where plants and animals live) to mental model two (a place that supports life). Still, most of the fourth and seventh graders, regardless of whether they took a field trip, held mental model one.
The results for the seventh graders who participated in the Family Science Club were more dramatic. These students experienced an eight-fold increase in using Model 2 in their drawings. The researcher explains that this “indicates students understanding the concept that the desert is more than a venue but is itself an active natural world or ecosystem.” What's more, these students were the only ones to demonstrate an increase in sophistication in their models from before the assessment to after.
These family outings were clearly more effective at altering mental models. According to the researcher, “the Family Science Club events transpired quite differently than the classroom-based field trips. With three teachers, plus a volunteer astronomer, plus parents all on hand, the discussions about the environmental activities were numerous, participatory, and highly engaging.” By contrast, the class field trips “often involved one teacher, with raised voice, projecting directions to a large group of students.”
The author notes that many of the teachers in the experimental group mentioned informally that they were happy to give their students the chance to experience a natural area first hand. The author reflects, “Essentially, the teachers made a dangerous assumption that exposure to nature obliges deeper (or more connected) understanding. Unfortunately, this may too often be only a hopeful desire of educators who expose students to the outdoors but who do not deliberately plan to challenge students' conceptions . . . . ”
To be fair, the results of this research may be affected by the fact that the mental models used by the researcher to assess student comprehension were different from the specific learning objectives developed by the teachers for their students. The researcher notes that if the students and teachers knew that mental models would be used to assess students, activities that more explicitly used the models could have been developed so that students could learn to examine and refine their models, and, consequently, the results may have been different. And while the results for the group that also attended the family activities were dramatic, the researcher notes that this was a self-selecting group that could also have been more predisposed to learning about the environment.
The Bottom Line
Simply exposing students to the outdoors through field trips will not necessarily change their mental models of the ecosystem they're visiting. Changing their ideas about the complexities of the ecosystem requires more explicit instruction. The results of this study also suggest that intergenerational learning opportunities could help students think in more sophisticated ways. But it's not clear from this research what aspects of an intergenerational learning activity were most responsible for positive results, as the intervention also involved other differences from a standard field trip, including a greater variety of hands-on learning opportunities and a greater number of site visits.