# Everyday Physics: Dancing

by Sarah McPherson, AP Physics 1

When looking at a dancer, the eye sees impressive movement. Behind every performance are hours of practice, sweat, and dedication. After it’s all broken down, one can find the clockwork in dancing – physics.

A major factor in dancing is balance. Dancers have to focus on their centers of gravity when performing, for if they lean too far forward, their center of mass could go beyond the base of support, and they could fall. Balancing is even more difficult if there are partners dancing together; however, dancers can use physics to their advantage. If their centers of gravity are used correctly, the end result can be a stunning visual. For their centers of gravity to be supported, physical connection, or tension, is needed. The partners pulling on each other can help each other balance. The diagram below is a great illustration of the forces working on them.

The force of gravity is pulling them down and keeping them on the floor; likewise, the weight vectors from their centers of gravity point directly down, even though they are slightly tilted. Without the tension of their arms holding each other, both of the dancers would more than likely fall – especially the girl. Holding themselves together in this fashion creates one unit with a center of mass located somewhere between each dancer and over the base of support offered by the male dancer’s feet.

Physics also applies to swing dancing. This partner dance requires focus and momentum. For example, a very famous move in swing dancing is called “The 6 O’clock.” The female partner is directly above the male partner with her arms wrapped around his neck. The female is representative of the hour hand while her counterpart is the minute hand.

In order to reach this position, the female has to get a running start to reach the male, and then jump high enough for him to catch her. The woman’s kinetic energy during running is converted to gravitational potential energy with the assistance of the man performing work to lift the woman higher.

Though it may seem unlikely, physics is a key part of dancing. Without this science, the dancers wouldn’t be able achieve certain movements and the dance would be dull. Physics brings excitement to the dance!

Reference: http://www.hep.uiuc.edu/home/g-gollin/dance/dance_physics.html.

About the author: Sarah McPherson is a student in AP Physics 1 and is also the Drum Major for the Marching Grizzlies. In addition, she is the artist of the featured image in the page header.

# Roller Coaster Physics

Carden with his model “G Money.”

### The creation of a model:

Kendra and Leslie with their model of “No Clue.”

By kimgeddes

# Earth, Physics and Imagination

by Leslie Medina, AP Physics 1 student

Painting by Leslie Medina

When I think of Mother Earth, I imagine hearing a pulse, and I visualize all the natural beauty that Earth contains. When I give such human-like qualities to Earth, I envision her breathing, even though I know this is not how things work. I think about all the possibilities and opportunities that Earth has given us. The ability to live, explore, and gain knowledge about our universe and the galaxies that endlessly fascinate us. When I depicted Earth breathing and exhaling, I was visualizing how Earth metaphorically takes in knowledge of its surroundings.

With this knowledge, there is an even greater desire to learn more about Earth, space, and life itself. Physics explores many things concerning these expansive topics and attempts to offer an explanation of all the extraordinary phenomena that surround us. On my painting, various equations and key details concerning gravity, orbits, and planets, appear as stars in the night sky. What I’ve come to realize is that these equations not only fill up the background space of my painting, but they also fill up the spaces in our curious minds with an abundance of knowledge.