Have you ever been to a circus, amusement park, or stunt show? Well, all of those air defying and gravity smashing stunts are just good applications of physics and an understanding of motion. Not to say that these tricks are not dangerous and don’t risk life and limb, they do. However, the physics principles behind them are rather simple. Take for example the “Sphere of Fear,” “Globe of Death,” or “Circle of Doom” that is a staple in many circus acts. The stunt is fundamentally composed of a large spherical metal cage with one or more motorcycles and riders driving around on the inside. Created by Herb “Daredevil” Durkin after WWII, he and his wife believed that the public would pay good money in order to see the death defying “double loop.” For more than 30 years, they continuously added new tricks to their repertoire such as sidecars, more riders, and eventually, they decided to cut off the bottom half of the sphere in order to increase the risk and make it more exciting for the audiences. In the early 70s, Herb Durkin and his wife retired and left their “Sphere of Fear” to rust into scrap metal. From then on, fresh and innovative performers, entertainers, and daredevils have created similar acts and amazed audiences with their fearless acts of bravery.
Now onto the Physics!!!
Here is a “Prezi” that can explain everything: "The Sphere of Death" - Prezi
In this "Prezi," you will find a description and analysis of the motion of the riders and motorcycles when riding in the "Sphere of Death." It includes a detailed description of both vertical and horizontal loops, what would happen if the riders go too fast, too slow, or just the right speed, and multiple FBDs and diagrams in order to help you understand what is the physics behind this amazing feat. To navigate the "Prezi," move the mouse to the bottom right of the "Prezi" and use the arrows to step forward or backward in the path.
Now that you know how it works, test you skills with the Homer Simpsons "The Ball of Death Game".
Black and Blue Colorful Fractal: http://www.shutterstock.com/pic-43038823/stock-photo-colorful-abstract-fractal-background.html
Blue and White Waves: http://www.shutterstock.com/pic-32752504/stock-photo-animated-waves.html
Dark and Gloomy Sphere of Death: http://picasaweb.google.com/lh/photo/3_vtdoqr_isY-Q69Qq8o6w
Green Sphere of Death in Motion: http://www.flickr.com/photos/mikerollerson/3332074252/
Blurred Motorcycle in Motion: http://www.flickr.com/photos/mikerollerson/3344932877/in/pool-fairgrounds
Sphere of Death in Daylight: http://www.sciencejoywagon.com/physicszone/03circular-motion/sphear/
Inside Sphere of Death: http://www.sciencejoywagon.com/physicszone/03circular-motion/sphear/
Bright Colorful Blue Fractal: http://www.shutterstock.com/pic.mhtml?id=41864677
Roller Coaster: http://sciencefair.math.iit.edu/projects/forces/
LED Circle: http://hacknmod.com/hack/goliath-killing-led-bola-slingshot/
Snail Cartoon: http://www.toonpool.com/cartoons/Globe%20of%20Death_9499#
Specific Tricks: http://www.acmecompany.com/Pages/Urias.html
YouTube Long: http://www.youtube.com/watch?v=PVaKxNDNF-Q
YouTube Short: http://www.youtube.com/watch?v=e3nqUUGWx4o&feature=related
Homer Simpson Ball of Death Game: http://www.gamesplz.com/play/457/homer-simpsons-the-globe-of-death.html