Angry Birds and R2-D2 Analyzed

Earlier this month the university sponsored a lecture titled: The Physics of a Flying R2-D2 and Other Interesting Ideas. Featured speaker Rhett Allain blogs about physics for Wired Science. During his lecture at Cornell, Apr. 4, Allain discussed some of his latest work and provided an analysis of the popular game Angry Birds. He also demonstrated for the public the newest Angry Birds game, Angry Birds Space, has both gravitational and frictional forces that can be modeled using physics.

Allain initially began blogging back in 2008 as a means to help his students at Southeastern Louisiana Univeristy better understand his physics lectures. He researched how students understand physics and developed better techniques to teach students. Allain admitted that while his first blogs may not have helped his students as much as he had hoped, he became a “blogspert” by posting analyses of physics examples for his own enjoyment.

Allain created his own experiments with Angry Birds Space and tried to recreate the conditions existing in the game. He made a model system using computer programs VPython and Tracker Video Analysis and estimated different aspects of the Space system including the force of gravity and friction on the bird, and the energy, change in momentum, and speed of the bird.

He said that applying these concepts to something as popular as Angry Birds is just the thing that will attract students’ attention. But Allain blogs this kind of analysis for fun. For him, the game is not to destroy the green pigs, but to match his model as close as possible to the game. He compared the process for figuring out how to model to climbing a rock wall. “It’s the practice that counts. The process of going up higher that counts. The goal is not just to get to the top, or there would just be an elevator.”

Allain was able to recreate the space conditions used in Angry Birds using classical Newtonian physics that apply to this universe and galaxies far far away, but Star Wars droid R2-D2 did not fly correctly according to Newtonian physics he said. In Star Wars R2-D2 is shown flying forward at a constant speed using thrusts that are at an angle, and when R2-D2 stops the thrusts are vertical.

“No one really notices that R2-D2 is flying wrong because it seems normal, it is what they expect. This is the same problem students have in introductory physics ...even though they know to say the right answer about force and motion, they still think that constant force means constant speed.”

R2-D2 flies more accordingly to Aristotelian Physics Allain said. According to Aristotelian Physics no force means no motion, and if there is constant force there is constant motion. According to Aristotle if there is a force of gravity then the thrusts must do two things: support the droid and push it forward. Newton’s first law of motion is that force changes motion, so if something is already in motion it will continue to move unless there is another force. R2-D2 should not have thrusters that apply a force at an angle Allain said.

Allain also examined what it would take for a human to fly with wings, which was sparked by a video posted on the internet. “How big can you get and still [be able to] fly?” Allain asked. “We have this idea, if something is bigger, it is going to be just like something smaller. Things don’t scale like you would think.” By taking some data from Wikipedia, Allain created a plot of mass versus wingspan, and determined that the subject in the video could not have actually been able to fly. Allain’s blog also includes some more technical reasons that involve video analysis.

One could call Allain a mythbuster of sorts, and in fact he has worked with the producers of the popular Discovery Channel television show providing them with some plausible calculations and advice on their experiments. Allain said that he respects the mythbusters because a lot of the time they do things quite accurately.“ They promote science because they are not scientists... They are people doing science project type things with explosions and expensive stuff which makes it so appealing.”  

Like the mythbusters, Allain spent his time writing about what he wants to find out, if it is something he actually examine. “I’m writing more for myself, that is what helps me keep on doing it. I am very lucky to have people who also enjoy it.”