Using Written and Pictorial Tasks to Analyze Middle School Students' Models of Phase Change

• In Event: Roundtable Session 2
  In Roundtable Session: Connections Between Drawings and Written Text in Student-Generated Particle Model Realizations

Abstract

1. Objectives
This study describes student learning about phase change with simulations that differ in the level of engagement. We examine the difference in the ways students translate the knowledge they acquired in the simulations into static pictures and written text.
2. Perspective
Simulations are becoming increasingly popular in learning about the realm of particles. The level of participation in the simulation can vary from passive observation, through manipulation of sliders and controllers to participating in the construction of the rules of interaction of the computational model.
3. Method of inquiry
Approximately 120, 8th grade students from a public middle-school in the southwest US participated in the study. The study encompassed three science class focusing on particle model explanation for phase change. The students were assigned into a control group – studying a regular, non-participatory simulation, and experimental group in which they engaged actively in moving particles in the simulation.
4. Sources of data
We used pre and post questionnaires that asked students to draw the approximate configuration of particles at three points of time of the graph in Figure 2.
This task illustrates several aspects of the students’ mental models of the boiling process and its relation to the heating curve. For example, in Figure 3 the student identified point A as water being in the solid state (when in fact it is liquid), drawing A, B and C as the three states of matter.
In addition to drawing, students were asked to explain in writing what happens to the water molecules during the time between B→C.
5. Findings
Students that were assigned to the more active simulation mode, outperformed the control group in a post activity in the correctness and accuracy of both written and pictorial responses. Analyzing the written responses vis-à-vis the pictorial representations, revealed three types of relationships between pictorial and written answers: congruence, contradiction, or complementarity. Drawings and written explanations that are congruent share at least one, obvious feature. For example, student #430 wrote: “The water molecules are constant because the water is started to boil so it will stay the same” and drew an identical particle configuration in boxes B and C. Conversely, some pictures contain features that contradict the information provided in the written response. For example: Student #514 wrote: “The water molecules start to evaporate during this time because the heat is rising in the water” but drew the same water level in boxes B and C, and no vapor particles about the liquid level. Finally, ‘complementary’ pictures and written explanations, provide different bits of information in the two modes that are unique to the specific mode of expression.
6. Scholarly significance
We use this categorization to differentiate between mental models of the phase change process that emerged among students who used the more active simulation (the experimental group) and those who used the equivalent, more traditional simulation. We show that although students in the experimental group performed better than those in the control group, their written and pictorial models were less congruent and not as well aligned.

Author

• Elon Langbeheim, Arizona State University - Tempe