This Taiwanese study examined how effective an analogy, involving roleplay, is at helping students overcome their misconceptions about phase changes (identified prior to the study in a literature review). The paper shows that the analogy has a significant impact on students’ (aged 13–14) conceptual change in the long term.
Using the activity proposed in the study (detailed below) was effective in challenging students' conceptions about the motion of particles in different phases and was significantly better for retaining knowledge: the performance of the control group regressed dramatically within four weeks and the experimental group did not.
- Particles in the liquid state are bigger than those in the gaseous state.
- Particle size increases when heating occurs.
- Particles in the liquid state and gaseous state are smaller than those in the solid state.
- Particles melt when heated.
- Water changes to oxygen and hydrogen when evaporating.
- Bubbles in boiling water are made of oxygen and hydrogen.
- Water condenses from gaseous hydrogen and oxygen outside a cold jar.
- Particles in the liquid and gaseous state are in motion but there is no particle movement in the solid state.
- There is no change in the distance between particles in different states.
- Teachers could employ similar activities to those used in the study to illustrate the microscopic view of chemical reactions.
To examine the effectiveness of an analogy activity designed to overcome students' misconceptions about the microscopic view of phase change.
83 students were randomly assigned to either a control or an intervention group. The control group received traditional-approach instruction and the intervention group received instruction using the analogy activity as follows:
- Students were split into pairs.
- The teacher informed all students that they were identical Bromine atoms, and the two-person teams needed to hold hands in all situations.
- The teacher then told students they were to imagine it was -10°C (in Bromine's solid-state): They were asked to cram together and dance slowly to illustrate the minute motion of Bromine molecules in this state.
- This was then repeated for 20°C (the liquid state): Students were asked to move more vigorously, and the space between the pairs naturally became larger to facilitate this motion.
- Finally, it was repeated at 75°C (gaseous state): Students were asked to move even more vigorously at greater distances.
Students took pre- and post-instruction tests, with a follow-up after four weeks. All tests required drawing particle pictures for the different phases. They were also asked to draw at least two sets of molecules or atoms of the substance for each phase. Teachers independently assessed responses for misconceptions, categorized as 'correct,' 'incorrect,' or 'unidentifiable.' Responses were then statistically analysed using chi-squared.
Details of the sample
The sample consisted of 83 Taiwanese students (aged 13-14) from a suburban school in Taipei City. The control group contained 42 students and the experimental group contained 42 students.