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Steven D. Gammon
Animating Graphical Data during Lecture To Simulate Real-Time Data Collection
Western Washington University Bellingham, WA 98225-9150
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Brian K. Niece Assumption College, Worcester, MA 01609-1296;
[email protected] Current multimedia computer capabilities have transformed the chemistry lecture. In a recent comment in this Journal, Richard Zare points out the “importance of graphical material in telling our story of what we do” and goes on to note that all chemists can now produce their own multimedia materials (1). A desktop PC is capable of producing color, threedimensional, and even animated images. Burke, Greenbowe, and Windschitl have suggested guidelines and a strategy for developing animations of chemical phenomena (2), and Sanger et al. have provided evidence that animations help to improve students’ conceptual understanding of chemical behavior (3). The ability to import data from a spreadsheet or instrument into presentation software, such as Microsoft PowerPoint, has increased the ease with which real data can be included in a multimedia lecture. However some data, such as voltammetric scans and chromatographic runs, have a temporal or directional nature that is not adequately expressed by a static graph displayed on the computer screen. In fact, computer display of such data has little advantage over conventional overhead transparencies. It would be ideal to use the computer to simulate the development of a line graph over time as it occurs in the laboratory. Unfortunately, as Burke et al. point out, development of effective animations is a time-consuming process that may require the involvement of multiple people with diverse skills (2). A few utilities have been developed to allow quick generation of animations via the Web, such as that presented by Stueker, et al. (4). Desktop molecular modeling software can also be used to produce animations of reactions and molecular vibrations. Unfortunately, these easy-to-use tools generally have a single purpose, such as animating a molecule or reaction, and cannot be adapted to animating a graph. However, I have found a quick way to animate two-dimensional data
Figure 1. Slide with axes before addition of data to be animated. The screen is shown as it appears in PowerPoint for Windows 2002.
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for display in lecture using PowerPoint; examples are provided in the Supplemental Material.W A simple graph can be animated in only a few more steps than are required to import a static graph into PowerPoint. First, the axes of the graph are imported as a graphic or drawn directly on a PowerPoint slide, as shown in Figure 1. Next, the graph is copied from the spreadsheet or other program and pasted on top of the axes as a second graphic, like the simulated polarogram shown in Figure 2a. Finally, a custom animation is added to the image of the graph using the “Wipe” entrance effect with the direction set to “From Left” and the speed set to “Very Slow” as shown in Figure 2b.2 During the presentation, the slide will initially display only the axes. Clicking the mouse button will result in the appearance of the polarogram from left to right across the screen as it would be drawn by a chart recorder pen. The “Very slow” speed causes the graph to appear over the course of about five seconds, which is much faster than an actual polarogram,
Figure 2. Slide including graph data. (a) Full screen view. The open circles and the numeral one indicate the boundaries of the graph to be animated. (b) Enlarged view of animation settings used to simulate the graph being drawn on the screen. The effect “Wipe” was chosen from the “Entrance” submenu of the “Add Effect” button. The screen is shown as it appears in PowerPoint for Windows 2002.
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but slow enough to help the students visualize how the data would be produced by an instrument. A PowerPoint presentation containing several animations, including the examples used here, is available in the Supplemental Material.W A more complicated graph can be divided into parts. For example, in teaching cyclic voltammetry, it is desirable to display the various segments of a voltammogram one at a time, emphasizing the direction of the sweep, but pausing to discuss the chemical reactions occurring at each point. The strategy for accomplishing this is shown in Figure 3. In this case, the graph and axes are placed on the slide as a single graphic. Opaque white boxes are then drawn covering the various parts of the graph that are to be sequentially uncovered. (For clarity, these boxes are shown as numbered, gray outlines in the figure.) Each box is given a custom animation that will occur in the order indicated by the box numbers. All four boxes are set to exit using the “Wipe” effect and the “Very Slow” speed. Boxes 1 and 2 have the direction set to “To Left” while boxes 3 and 4 have the direction set to “To Right.” As a result, the voltammogram will appear to be drawn on the screen in four sections, pausing after each to allow the instructor to explain what is happening at that point. A mouse click will cause the next section of the graph to be revealed on the screen. The top two sections will be drawn from left to right, and the bottom two will be drawn in from right to left as expected for a cyclic voltammogram. The techniques described above can be used for any graph that has a time or direction dependence that we wish to demonstrate to the students. In an instrumental analysis course, I have used it for voltammetry and chromatography as suggested above. In a general chemistry course it could be used to show heating and cooling curves in thermodynamics, reaction coordinates for kinetics and equilibrium, and titration curves.
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Notes 1. The technique described has been tested in Microsoft PowerPoint for Windows, versions 2000, 2002, and 2003, and PowerPoint for Macintosh, version 11.0 (2004). 2. In order to add the custom animation, select the graph with the mouse and then click “Custom Animation” on the “Slide Show” menu. In PowerPoint 2002 or 2003 for Windows, select “Entrance” and then “Wipe” from the “Add Effect” menu, then select “From Left” in the “Direction” box and “Very Slow” in the Speed box. In PowerPoint 2000 and earlier for Windows, select “Wipe” in the “Entry Animation and Sound” box and “Right” as the direction. In PowerPoint 2004 for Macintosh, click the “Add Effect” button, select “Entrance” at the top of the resulting dialog box and “Wipe” from the list, then click “OK.” Set the “Property” box to “From Left” and the “Speed” box to “Very Slow.” Note that exit animations and the speed choice are not available in PowerPoint 2000 for Windows and earlier. The animation speed cannot be set in PowerPoint X for Macintosh, and this and exit animations are not available in earlier versions.
Supplemental Material A PowerPoint presentation containing the animations presented in this paper along with several others is available in this issue of JCE Online. W
Literature Cited 1. Zare, Richard N. J. Chem. Educ. 2002, 79, 1290–1291. 2. Burke, K. A.; Greenbowe, Thomas J.; Windschitl, Mark A. J. Chem. Educ. 1998, 75, 1658–1661. 3. Sanger, Michael J.; Phelps, Amy J.; Fienhold, Jason J. Chem. Educ. 2000, 77, 1517–1520. 4. Stueker, Oliver; Brunberg, Ingo; Fels, Gregor; Borkent, Hens; van Rooij, Jack. J. Chem. Educ. 2003, 80, 583.
Figure 3. Slide showing the outlines of boxes for sequentially uncovering various par ts of a cyclic voltammogram. (a) Full screen view. Boxes have been shaded gray for clarity. For presentation, they should be opaque white with no border. (b) Enlarged view of settings: the effect “Wipe” was chosen from the “Exit” submenu of the “Add Effect” button. The screen is shown as it appears in PowerPoint for W indows 2002.
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