College student guide: laboratory experiment to measure thermocapillary force and demonstrate microbubble trapping

Abstract This paper presents a laboratory experiment designed for college and undergraduate students to measure thermocapillary force (Marangoni effect) and demonstrate the trapping of microbubbles, a phenomenon arising from temperature-induced surface tension gradients along fluid interfaces that causes fluid motion towards the regions of lower surface tension. Despite its significance in microfluidic systems, bioengineering, and precision manufacturing, the thermocapillary effect is often overlooked in standard curricula. The suggested experimental setup allows students to manipulate microbubbles in a liquid using temperature gradients induced by a low power laser, helping them explore fluid dynamics, surface tension, and temperature gradients in a controlled environment. The experiment not only reinforces fundamental physics principles but also highlights real-world applications such as drug delivery, micro-manufacturing, and tissue engineering. By providing hands-on experience, the experiment bridges the gap between theoretical knowledge and practical applications, offering a cost-effective tool for fostering a deeper understanding of fluid mechanics and thermodynamics in the classroom.