Using Simulations on Mobile Devices in Class

Colleen Countryman, North Carolina State University
Wolfgang Christian, Davidson College


Following the tradition of micro-computer based interactive lecture demonstrations (ILDs), we developed a series of web-enabled interactive lecture demonstrations for students’ smartphones and tablets. Effectiveness of ILDs for introducing physical concepts has been demonstrated, and there is evidence of significantly improved "learning and retention of fundamental concepts" with students that participate in ILDs.1 Now, students’ personal electronic devices provide us with further opportunities to engage them in these interactive activities. In particular, one study indicates that the use of students’ smartphones as data collection devices in introductory labs can strengthen their beliefs about real-world connections, and improve their attitudes about the labs.2


The web-based environment used in these simulations does not require an additional app download. In fact, students can access the simulations through their smart device’s built-in browser. The simulations use the Physlet approach presenting students with small, single-concept interactive exercises embedded in a web browser,3 however these simulations are unique in that they collect acceleration data from the smart devices’ internal sensors to impact the motion of the objects of interest in the simulations. Simulations used in the book are distributed with source code through the Open-Source Physics collection hosted on the AAPT ComPADRE website. The simulation source code can be edited, recompiled, and redistributed using the Easy Java/JavaScript Simulations (EJS) authoring and modeling tool developed at the Universidad de Murcia, Spain, by Francisco Esquembre.4 The only restriction is that these JavaScript simulations must be distributed at no cost under a Creative Commons Attribution-NonCommercial-ShareAlike license.

Our mobile device simulations have been collected and augmented with activities in Mobile Device Models,5 a ComPADRE digital book of explorations, problems, and lecture demos. The activities were the result of examining the learning objectives of a typical introductory physics course, and determining opportunities which could most effectively utilize simulations with controls based on the movement and physical orientation of the device and they are currently being tested at NC State University at Raleigh.

Simulations and Data

Mobile Device Models features eight different simulations intended for introductory and advanced mechanics classes. We will discuss two in detail here.

First, in the "block sliding on an incline plane" simulation, a block rests on a table with friction. A free body diagram of the block is drawn. The surface of the plane is fixed to an edge of the smartphone so that as the smartphone rotates, the block experiences a component of the gravitational pull down the inclined plane. The goal of the activity is to determine the static (and, ideally, kinetic) coefficients of friction between the block and the plane.

This simulation and accompanying activity were piloted at North Carolina State University in an introductory calculus-based large-enrollment physics course. Before introducing the simulation, students were asked to work in teams of two to draw a Free Body Diagram of a block on an inclined plane, and determine an expression for the coefficient of static friction between the block and the plane.

Students were then asked to navigate to the simulation with their smart devices, and determine the coefficient of static friction between the block and the plane in the simulation. 94% of our 165 study participants brought a smartphone or tablet. The others shared with their partners. 76% of students obtained the correct coefficient of static friction. Given more time, students could have also been asked to determine the coefficient of kinetic friction.

Secondly, we adapted and piloted a molecular dynamics simulation first developed by Dan Schroeder.6 In the modified simulation, simple molecules in a two-dimensional container respond to the gravitational sensors as well as adjustable thermal parameters. Although the value of the gravitational acceleration is not to scale for a molecular model, the simulation allows students to qualitatively explore the connection between micro- and macroscopic properties of matter, such as the change in density in a gas acted on by an external force.

After a brief lesson on the kinetic theory of gases, students were asked conceptual Clicker questions regarding their expectations of the molecules’ motion and average kinetic energy of molecules, as well as the structure of the system of molecules as heat is added. Then, students were asked to explore the simulation and determine how the molecules react to rotation of the screen, and heat added to or removed from the system (in terms of the molecules’ color, average speed, total energy of the system, and structure of the system). For an additional challenge, students were asked to try to return the molecules to their original state.

With self-reported data after each simulation activity, we determined that students’ attitudes during these activities were consistently positive. More than 60% of the students agreed or strongly agreed that the group work and simulations aided their understanding of the topics at hand, and more than 64% of the students indicated that they would like to do more activities like these in class.

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The free body diagram in the “Block on an Incline Plane” simulation responds to the orientation of students’ smartphones.

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Molecules in the simulation clump in the lower right hand corner in response to the orientation of the smartphone.

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Instructors can capture the accessibility of Interactive Lecture Demonstrations by utilizing the internal sensors within students’ smartphones. These new technologies paired with the accessibility of the AAPT ComPADRE digital library allow instructors an opportunity to deliver engaging and interactive content freely to their students. Students have reported that these simulations, paired with thoughtful group work aid their understanding and our survey data contributes to a positive affect.

Colleen Countryman is a Teaching Assistant Professor of Physics at North Carolina State University. She acquired her Ph.D. from NC State in 2015, specializing in Physics Education Research under the guidance of Dr. Robert Beichner and Dr. Michael Paesler. She has researched the impact of various educational technologies, including smartphones in physics labs, YouTube videos as resources to bridge math and physics classes, and online reading quizzes to promote preparation for class.

Wolfgang Christian is Emeritus Professor of Physics at Davidson College where he taught for 33 years. He is a fellow of the APS and of the AAPT and he is the author or co-author of nine books including: An Introduction to Computer Simulation Methods: Applications to Physical System (Addison Wesley 2006) and Physlets: Teaching Physics with Interactive Curricular Material (Prentice Hall, 2001). He was Chair of the APS FEd in 2003and he was the co-Chair of the 2008 Gordon Research Conference on Physics Research and Education.


1 Sokoloff, D. and Thornton, R. "Using interactive lecture demonstrations to create an active learning environment: AIP Conference Proceedings: Vol 399, No 1." 1997. Web. 12 Jan. 2017.

2 Countryman, C. L. "The Educational Impact of Smartphone Implementation in Introductory Mechanics Laboratories." (2016). PERC 2015 Proceedings.

3 Christian, Wolfgang et al., "The Physlet approach to simulation design," The Physics Teacher, vol 53:7, 419-422 (2015);

4 Esquembre, F., "Easy Java Simulations: a software tool to create scientific simulations in Java," Computer Physics Communications, vol 156.2, 199-204 (2004)

5 Christian, W., Countryman, C. and Esquembre, F. "Mobile Device Models." n.d. Web. 12 Jan. 2017.

6 Schroeder, D., "Interactive molecular dynamics," American Journal of Physics, vol 83:3, 210-218 (2015)

Disclaimer – The articles and opinion pieces found in this issue of the APS Forum on Education Newsletter are not peer refereed and represent solely the views of the authors and not necessarily the views of the APS.