The Science Behind the Scenes


The cast of Circus explains the science behind the scenes of the Big Apple Circus. See how the natural world creates unnatural wonders. Circus begins Wednesday, Nov 3 at 9pm on WGBH 2 (view clips and schedules).

Centripetal Acceleration

Trick riders may just ride in circles, but that doesn't mean they aren't accelerating. Moving in a circle requires steady changes in direction. This is a form of acceleration directed inward, the same acceleration that we feel when going around bends in a car, and that holds us in our seat on the rollercoaster. In this video, you'll learn the basics of circular motion.

Conservation of Angular Momentum

Ever notice how flying acrobats, gymnasts, ice-skaters and half-pipe snowboarders, tuck in their arms and scrunch up their bodies while spinning in the air? By keeping their arms and legs tucked close to their centers of mass, they are able to rotate faster. This is because, just like linear momentum, the momentum of rotation, called angular momentum, is also conserved.

Conservation of Energy

The aerial acrobatics of the Russian Barre routine require exquisite balance, timing, and years of training. That's not enough though; conservation of energy plays a big role as well. This video explores the basics of the three common forms of energy: potential, kinetic and elastic.

Linear Momentum

Platform trapeze requires athleticism, good timing, and a strong understanding of the principle of conservation of linear momentum. The momentum of a system is the sum of the momenta of all the objects in it. Like energy, the momentum of a closed system is always conserved. In this video you'll learn how platform trapeze artists use this fact to soar beneath the big top.

Newton's Laws of Motion

The dog show looks like chaos in the ring, but the commotion can be explained by just three simple laws of motion. Objects in motion tend to stay in motion. Force equals mass times acceleration. And for every action, there is an equal and opposite reaction. Learn how these three laws--Newton's Laws of Motion--can help make sense out of the outrageous antics of the dog show.

Pendulum Motion

Swinging back and forth, the solo trapeze is a giant pendulum, just like the one in a grandfather clock. The time it takes to swing forward, then back to where it started is called the period. Surprisingly, this time has very little to do with the height of the swing. It depends mainly on the length of the pendulum, the longer the pendulum, the longer the period.

Projectile Motion

Jugglers know that if you throw an object into the air, it will follow a curved path -- as the ball moves horizontally, gravity pulls it down vertically. Physicists call this projectile motion. In this video you will learn why projectile motion is important to jugglers and why it is so hard to juggle multiple objects.

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