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Real-World Physics Via the Web


Jon M Pearce, School of Physics, University of Melbourne, Parkville, Vic 3052, Australia. Phone +61 3 9344 8072 Fax: +61 3 9347 4783. Email: jonmp@unimelb.edu.au Home Page: Jon Pearce

Michelle K Livett, School of Physics, University of Melbourne, Parkville, Vic 3052, Australia. Phone +61 3 9344 8071 Fax: +61 3 9347 4783. Email: m.livett@physics.unimelb.edu.au


Keywords: WorldWideWeb, Video Analysis, Physics, Spreadsheet, Modelling

Physics and Reality

Students of first year physics are often heard to comment that physics is "not real", "theoretical" and "unrelated to the real world". This poster reports on the early stages of a project funded by the Committee for the Advancement of Undergraduate Teaching (CAUT) which aims to address this "relevance" problem in physics teaching whilst also confronting students' misconceptions in physics through a highly interactive computer package.

The Web was chosen as a delivery method due to its "any time, any place, any platform" offerings. This was considered important for the usual pragmatic reasons, but also because we want students to be able to take out of the lab or lecture theatre some of the experiences that traditionally get left behind as they leave: demonstrations that are worth revisiting in their own time; practical experiences that fly by in a blur during the usual frenzy of an afternoon laboratory session as well as the wealth of real-world examples of physics in action.

Description of the software

The software comprises three parts: an HTML "front-end" which introduces several student assignments and presents some of the physics theory. This is followed by a complex Java-coded analysis tool in which students will analyse videos of real-life physics, carry out spreadsheet modelling and explore graphs and vector representation of motions. Finally students are given an opportunity to "interview" on-screen a person involved in the video in order to explore how that person views their actions in relation to the physics being presented. Since, at present, most of the current effort is being put into the Java-coded analysis tool, only that part is being presented in detail in this poster.

An applet for analysing motion

This applet enables students to analyse frame-by-frame a video of a real-world event, such as a long jumper. It displays on screen two or three "objects", where each object can be one of: a QuickTime video display; a spreadsheet; a graph; a vector display.

Video

The QuickTime video display enables students to choose a video from a pre-recorded set and analyse the motion of objects by clicking on the location of the objects on each frame of the video. These data are stored in a spreadsheet (also part of the Java applet) and are linked so that future editing of these points, by dragging with the mouse, will cause the values in the spreadsheet to update.

Spreadsheet

The spreadsheet is set up to record the video data as three-dimensional vectors (although the third dimension is not used for video information). Once these data are entered, the spreadsheet can be instructed to display kinematic vectors (position, velocity and acceleration) superimposed onto the video display. Other quantities, such as momentum, energy, etc., can be derived from these data by the use of spreadsheet formulas that the student enters. These derived quantities can be displayed on a graph or within the vector display area (see below).

An innovative aspect of this spreadsheet is that, in addition to its ability to carry out conventional spreadsheet operations, it accommodates three-dimensional data. That is, the vector information is stored as x-y-z components and functions are built into the spreadsheet to perform vector operations. All three dimensions come into play for vector operations. For example, the vector cross-product transforms inputs in the x-y plane into a vector in the z-direction. This is important for the study of rotational motion and that of electric charges moving through magnetic fields. Inclusion of features such as vector operations make this spreadsheet much more powerful for science-type modelling than a traditional financial spreadsheet.

Display: graphs and vectors

The output of the spreadsheet can be displayed on a graph in a conventional manner. However, it can also be displayed as a set of 3-d vectors located in the x-y-z coordinate system. This means that students can analyse a video, calculate vector quantities such as force, momentum, torque, etc. and then see these vectors displayed as a sequence of arrows in order to help visualise the relations between them. The vector display allows students to view these vectors in three ways: located at the position of the object whose motion is modelled; in a time sequence across the screen; or collected with their tails coincident at a point. The vector display can be rotated in order to obtain different views of these 3-d vectors.

How does this help students learn physics?

Clearly the value of this package lies in its application as much as in its features. It is planned to develop structured assignments that encourage students to explore real-world events in a highly motivated way, and to use analysis tools to help students make explicit and explain their conceptions of the underlying physics. Although the analysis facility is an exciting and innovative tool, the project will maintain an emphasis on the satisfaction of discovering the physics underlying everyday phenomena.


Copyright

Jon Pearce, Michelle Livett ©, 1996. The authors assigns to Southern Cross University and other educational and non-profit institutions a non-exclusive licence to use this document for personal use and in courses of instruction provided that the article is used in full and this copyright statement is reproduced. The authors also grant a non-exclusive licence to Southern Cross University to publish this document in full on the World Wide Web and on CD-ROM, and for the document to be published on mirrors on the World Wide Web. Any other usage is prohibited without the express permission of the author.

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These pages are maintained by Jon Pearce ( jonmp@unimelb.edu.au), Department of Information Systems. The opinoins on them do not necessarily reflect those of the University of Melbourne. Tel: (613) 8344 1495 Fax: (613) 9349 4596. Last update: September 16, 2003 .