Student understanding of the direction of force due to atmospheric pressure: A tale of two models
Keywords:
atmospheric pressure, weight model, collision modelAbstract
The direction of force due to atmospheric pressure is a difficult idea for students to understand. We report a study, involving 35 middle school students, which points towards the existence of two contrasting mental models of atmospheric pressure(Patm), which we term the Weight Model (WM) and the Collision Model (CM). Our analysis reveals a predisposition among students to adhere to the WM, wherein they consider Patm akin to a column of air pressing down on the surface of the earth (Tytler,1998). In our presentation, we discuss everyday experiences and textbook presentations as two plausible sources for this predisposition.
Our study involves the analysis of the student discourse as they participated in an activity to estimate the value of atmospheric pressure using a syringe and some easily available materials (Inversin, 1977). Students worked in small groups of 3 to 4, facilitated by instructors. Our goal was to help students engage in discussion, wherein they explicitly articulated their ideas and considered notions from others in an authentic context, thereby paving the way for a revision of their own ideas. The activity had the following components:
a) A pre-activity questionnaire: A set of 6 questions, aimed at eliciting students’ prior conceptions and basic understanding related to atmospheric pressure. These written responses subsequently served as the basis for discussion among students, within and across student groups.
b) A demonstration to show the action of atmospheric pressure: Instructors illustrated the action of atmospheric pressure on the syringe and its directionality. The demonstration sought to scaffold students’ thinking while engaging with the difficult notion of the direction of force due to atmospheric pressure.
c) Activity to estimate the magnitude of atmospheric pressure: In this part the students have to design an experiment using the syringe to calculate the value of atmospheric pressure. The experimental design involves a balancing condition between 3 forces: static friction between the barrel and piston of the syringe, force due to atmospheric pressure and weight hung on the syringe.
d) Post activity questionnaire: The final part of the activity is a set of questions aimed at checking whether there was any change in student response patterns pertaining to atmospheric pressure.
Our analysis reveals that the activity and associated discussions show potential to facilitate students’ transition from the WM to the CM. We present evidence of modest conceptual gains characterized by micro-transitions in students’ problem-solving strategies, being increasingly inclined towards the canonical CM rather than the intuitive WM of the atmosphere. We also present some problematic discourse patterns, which are likely widespread in traditional lecture-based Physics classrooms.
REFERENCESInversin, A. R. (1977). Measuring Atmospheric Pressure with a Syringe. Physics Teacher, 15(4), 232-233.
Tytler, R. (1998). Children’s conceptions of air pressure: Exploring the nature of conceptual change. International Journal of Science Education, 20(8), 929–958. https://doi.org/10.1080/0950069980200803
Downloads
Published
Issue
Section
License
Authors who publish with the Proceedings of the International Conference on Physics Education 2022 agree to the following terms:
a) Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
b) Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
c) Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access - http://opcit.eprints.org/oacitation-biblio.html).
Privacy Statement The names and email addresses entered in the Proceedings of the International Conference on Physics Education 2022 site will be used exclusively for the stated purposes of this journal and will not be made available for any other purpose or to any other party.