Rachel Peters is making music with a laser.

As a chemistry major entering her senior year, Peters and Dr. Han Park, assistant professor of chemistry, are researching what is called the photoacoustic effect.

Discovered in 1880 by Alexander Graham Bell, inventor of the telephone, the effect occurs when light is absorbed by a material, such as glass or a mineral like selenium, and transformed into sound waves through changes in heat and pressure. The photoacoustic effect explains how sound can be generated by light.

Rachel Peters works in a lab in Grote Hall.

To create an acoustic sound wave in her experiments, Peters uses a laser to strike a glass tube filled with ethylene gas.

“When the laser hits the glass cell, the gas warms up, changes in pressure and generates a sound wave. I then use a high-powered microphone to record the sound,” she explains.

By changing the variables in her experiment, like the length of the tube or the concentration of the gas, Peters is able to change the frequency of the sound wave and create different musical notes.

So far, she has been able to record multiple, distinct notes and organize them into a musical scale. By the end of her research, she hopes to be able to record a full song to demonstrate the fundamentals of the photoacoustic effects and thermodynamics in a fun, engaging way.

“It would just be something simple, like ‘Twinkle Twinkle Little Star’ or ‘The Star Spangled Banner,’” she says.

When Park approached Peters to assist with his research, she jumped at the chance.

“UTC offers many opportunities for student research. It’s usually something that’s usually only available to graduate students at other schools,” she says.

“This experience has sharpened my critical thinking skills. Being in a lab, you can’t always predict what’s going to happen.

“I’ve also been able to use a lot more equipment than what I’ve used in the classroom. Doing something like this will give me an edge when it comes time to apply for graduate school.”

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