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This past Wednesday evening the CEID classroom filled with people young and old with one interest in common: bubbles. Dr. Larry Wilen used bubbles to illuminate topics such as the science of grain boundaries and the math of shortest distance problems.

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Participants learned that the hydrophobic and hydrophilic parts of soaps, or surfactants, help them to form films when mixed with water. Like many other physical phenomenon, the bubbles want to be in the lowest energy state possible. Due to the surface tension, which is related to the energy of the film, the preferred state of the bubble is when it has the lowest possible surface area.

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Dr. Wilen used the bubble’s desire to minimize surface area to demonstrate the easiest way to connect points in configurations ranging from a spherical tube to a map of cities in the United States. Participants found that different initial conditions can lead to various shortest paths. The obvious shortest path for a cylinder is a straight line, but when the cylinder was dipped the just right way into the soap solution, a spiral resulted. Dr. Wilen challenged the audience to make a spiral that wrapped around two or three times.

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At the end of the talk, Hanoi Hantrakul, an undergraduate physics major, shared his technique for making enormous bubbles with only his hands, shampoo, and water. After covering his hands in shampoo mixed with water, he blew into the fingers on one hand while holding the bubble with his other.

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After the demonstrations, the people attending the talk got to experiment with the bubbles themselves. Dr. Wilen shared his various bubble making tools with the participants while Hanoi shared his method for two people working together to blow the bubble. Everyone left the talk soapy and smiling.

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