Tuesday, August 07, 2012

Spandex Spacetime

Every summer, the Society of Physics Students selects a group of physics interns to work in the DC area on a variety of topics ranging from science history to public outreach. These interns aren't simply grabbing coffee and answering phones, however. Instead, you can find them devising new ways to inspire the next generation of scientists or conducting novel research.

The interns presented their final projects today on research, policy and historical science, but we're going to focus on some of the great outreach work a few of the interns have done. We're biased toward outreach here at Physics Central, but you can see highlights of all the interns' work on the SPS website.

For now, let's throw back to the 80's and create some spandex spacetime with a demo some of the interns worked on. Physics never looked so good.

SPS interns Melissa Hoffman and Meredith Woy worked on a spandex analog of spacetime. Using spandex and marbles, the interns could visually demonstrate how celestial bodies alter the geometry of spacetime.

In the video above, Melissa Hoffman and Meredith Woy show how a spandex sheet can mimic the spacetime that comprises the fabric of our universe. Using marbles, ping pong balls and well-placed gravity wells (aka pushing down on the spandex), Woy and Hoffman re-created cosmic motion in a 3rd grade classroom.

Weights placed in the middle of the spandex sheet could act as black holes while they slowly devoured unsuspecting marbles. Add another weight, and now you have a binary star system, significantly changing the marble and ping pong ball orbits. Gary White, the departing director of SPS, has even written an academic paper on the topic that unravels the analogies between Kepler's laws and spandex orbits.

While Woy and Hoffman worked on this and other projects, Physics Central team member the Mathlete guided intern Matthew Goszewski as he developed 12 different demos to compliment our Physics Quest effort. One such demo usually costs hundreds of dollars to create, but Goszewski put the demo together with office supplies costing about five dollars.

The original, more expensive setup for the experiment that Goszewski re-created for about five dollars.

In the video below, Goszewski shows how to pretty thoroughly mix a fluid and then completely revert the fluid back to its original, unmixed state. The setup involves a rotating cylinder resting inside of a larger container, and the intermediate space is filled with corn syrup or some other viscous fluid.

Goszewski's version of the laminar flow experiment.

The experiment shows laminar flow in action. When a liquid with the right amount of viscosity is mixed, it flows in a set of distinct layers. By rotating the fluid several times, the fluid mixes. When you rotate backwards though, the distinct layers unwind back to the original, distinct areas where they started.

Both Goszewski and Woy are working toward degrees in secondary physics education, so hopefully they'll be able to apply their summer work soon. Hoffman hopes to continue her physics research in graduate school, but all of the interns enjoyed their time working on outreach this summer.

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