Chemical Education Today
The VSEPR Challenge: A Student's Perspective by Ashley S. Jennings Hatboro-Horsham High School, Horsham, Pennsylvania 19044
The Presenting Problem In 2009, during my sophomore year at Hatboro-Horsham High School in Horsham, Pennsylvania, my chemistry teacher, Ms. Anderson, demonstrated different molecular structures of the valence shell electron repulsion (VSEPR) theory by using construction and assembly toys; specifically, K'NEX rods and connectors. She would put the K'NEX rods together in the shape of each structure and hold them up for the class. This let us see a three-dimensional representation of the molecule that our textbook could not show us. Although the demonstration was effective, my classmates and I later had difficulty remembering the molecular shapes when studying for the test, especially as the note cards we were studying from could only show us a two-dimensional image. In addition, our textbook represented molecular structures as lines and dots, which could become confusing to interpret. I knew how important it was to understand VSEPR theory because it tied together the other concepts of molecular chemistry we were learning about in class. I came up with the idea to make an animation that showed the VSEPR molecules as three-dimensional (3D) structures. I knew that 3D computer animation would work beautifully with the VSEPR theory. In 3D animation, once you create a model, you do not have to redraw each frame as in traditional, hand-drawn animation. Such animation would not only help me and my classmates understand the structures, but it would also do justice to the lesson our teacher was trying to convey. It could also be used by countless numbers of other students in the future. I approached my teacher about creating the video as a special project, and she agreed. What follows is the story behind how I made the Chemistry VSEPR Theory 3D animated video, which for the last 10 months has been posted and viewed on YouTube at http://www.youtube.com/watch?v=i3FCHVlSZc4 (accessed Feb 2010). Blending Science, Technology, and Art I have a strong foundation in science, mathematics, and technology; in addition, I have a keen interest in art, and I am always looking for ways to express my creative side by applying a blend of these skills. Growing up, I have been inspired by Disney animators and the 3D animation pioneered by Pixar Studios. In the summer after my first year in high school, I took a computer graphics class at the University of Pennsylvania, where I was introduced to the concepts of 3D modeling and animation. The primary tool used in the class was Autodesk Maya, a highend 3D modeling software package used in the movie and video game industries. Creating videos with Maya has since become my passion, and it was with Maya that I created the VSEPR animation in the spring of 2009. 462
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One lesson I have learned while working with computer animation is that, regardless of the project's complexity or how advanced the underlying technology is, the most important part of creating the animation is telling the story. In most cases, effectively communicating the story and creating a 3D animation consists of eight key steps: 1. Vision and Story: Define the project's objective, theme, and desired outcomes. 2. Concept Art: Outline the basic idea with preliminary conceptual drawings, which are generally drawn by hand. 3. Storyboarding: Depict the storyline, again using hand-drawn illustrations. 4. Modeling: Digitally “sculpt” shapes into the appropriate 3D models using the Maya software. 5. Texturing: Create the “skin” of the model by adding color and texture. 6. Rigging: Add a “skeleton” to the model; this will allow it to be animated. 7. Animating: Pose the models in a timed sequence within Maya to create the illusion of movement; this process is called keyframing. 8. Rendering and Editing: Make the computer reproduce individual frames as two-dimensional images, then add music, titles, and so on in an editing program.
The Animation Process To develop the VSEPR video, I wanted to replicate my teacher's demonstration, where each of the 12 VSEPR molecules could be highlighted and presented individually. To keep the viewers' attention, I determined that the video should be no longer than five minutes. To make the animation more interesting, I added a backdrop of freely floating glowing spheres that can be interpreted as electrons. To achieve this effect, I created approximately 50 small spheres, grouped them together, and set them up to rotate as a group. I also enhanced the lighting attributes on each sphere so they would appear to be glowing when the animation was rendered. Once the vision was established, I began drawing each of the VSEPR structures on a sheet of paper using rods and circles. I then used Maya to assemble the models, arranging cylinders and spheres in the program according to the shapes outlined in my notes. Once I had a structure I liked, I grouped the shapes so they would remain as one object. I omitted the texturing step, which is analogous to putting the detailed “skin” on the model, because the molecular structures did not need to be colored in detail. Instead, I added color directly to the model in Maya. In the color scheme I chose, the central atom is always blue, the outer atoms are white, and any lone electron pairs are red. Figure 1 shows an example.
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Vol. 87 No. 5 May 2010 pubs.acs.org/jchemeduc r 2010 American Chemical Society and Division of Chemical Education, Inc. 10.1021/ed100148e Published on Web 04/13/2010
Chemical Education Today
the molecules as they rotated and moved in and out of the screen. In total, nearly 3000 individual frames were keyframed and rendered to create a video that was 200 seconds long. As a final step, I imported the raw footage into the application iMovie and added music, stills (which included information about each structure), and the title sequences. For music, I selected Billy Joel's waltz “Nunley's Carousel” because it completed the mood I was trying to achieve and did not distract from the animation. Viewer Response and Next Steps
Figure 1. Two VSEPR models from the 3D animation created by the author.
Finally came the animation itself. As described earlier, my vision was to create a video that would show the formation of the different molecule types. I gave each molecule 10 to 15 seconds in front of the artificial “camera” of Maya, rotating them a few times in different directions so the viewer could get a general understanding of each model. This required keyframing the motion of
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Once I completed the editing, I presented a DVD to my teacher and then posted the video to YouTube. I was thrilled to see how much my teacher enjoyed the video, and I have been absolutely overwhelmed by the response the video has received online. To date, the video has been viewed more than 12,000 times by teachers and students from around the world. Many teachers have added it to their own Web sites as a learning aid for VSEPR theory. When I made the video, I never imagined that it would reach such a wide audience! I'm currently thinking about my next project and how to combine my passion with science to create additional learning aids. I am also looking at colleges that combine the interdisciplinary aspects of technology, fine art, and new media, and I would love to pursue a career in Disney Imagineering or Pixar Animation.
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Vol. 87 No. 5 May 2010
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