Abstract: The thermal expansion coefficient is a critical physical property parameter in physics and materialsscience, and its precise measurement is of great significance for verifying solid-state physics theories andindustrial applications. Traditional university physics thermal expansion experiments suffer from issues such asexpensive equipment, cumbersome operations, poor intuitiveness, limited measurement accuracy, and lowstudent engagement. To address these challenges, this paper designs a metal thermal expansion coefficientmeasurement device based on optical focusing and image analysis, combining optical imaging with digital imageprocessing to create a non-contact, high-precision, and low-cost visual measurement system. The system canmeasure and jointly solve for the thermal expansion of the longitudinal height and transverse diameter of ametal cylindrical sample, and then caleulate the linear expansion coefficient and bulk expansion coefficient.Experiments conducted with 6061-T6 aluminum alloy samples yielded linear expansion coefficients that closelymatched theoretical values, with a linear-to-volumetric expansion coefficient ratio of approximately 1 : 3,aligning with thermal expansion theory. This device effectively enhances experimental intuitiveness andoperability, providing a novel approach for university physics teaching and fostering students' practical andengineering skills.
