Major
Physics
Anticipated Graduation Year
2026
Access Type
Open Access
Abstract
In this project, we studied how the thickness of a soap film can be measured using the colors created by thin-film interference. When light shines on a soap film, some light reflects off the front surface and some off the back surface. These light waves combine and create colorful patterns that depend on the film’s thickness. By observing these patterns, we can learn how the thickness of the film changes over time.
We used two methods to collect data: a camera to capture the colors of the film and a phototransistor connected to an Arduino to measure the intensity of reflected green light. The data showed that the intensity of light changes in an oscillating pattern, which matches the expected behavior from interference theory. As time passed, the changes in intensity became larger, suggesting that the film was thinning and forming more defined patterns.
However, our results were affected by noise, air currents, and limitations in our equipment, which made it difficult to calculate exact thickness values. Even so, our observations agreed with the general theory. In the future, improving the setup—such as using a laser and better controlling the environment—could lead to more accurate measurements.
Faculty Mentors & Instructors
Dr. Jon Bougie, Professor, Physics
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.
Interference Colors to Thickness: Measuring Thin-Film Dynamics with a Camera and Arduino
In this project, we studied how the thickness of a soap film can be measured using the colors created by thin-film interference. When light shines on a soap film, some light reflects off the front surface and some off the back surface. These light waves combine and create colorful patterns that depend on the film’s thickness. By observing these patterns, we can learn how the thickness of the film changes over time.
We used two methods to collect data: a camera to capture the colors of the film and a phototransistor connected to an Arduino to measure the intensity of reflected green light. The data showed that the intensity of light changes in an oscillating pattern, which matches the expected behavior from interference theory. As time passed, the changes in intensity became larger, suggesting that the film was thinning and forming more defined patterns.
However, our results were affected by noise, air currents, and limitations in our equipment, which made it difficult to calculate exact thickness values. Even so, our observations agreed with the general theory. In the future, improving the setup—such as using a laser and better controlling the environment—could lead to more accurate measurements.