Introduction:
In recent years, particularly after the COVID-19 pandemic, many students have become increasingly disengaged from conventional classroom learning while spending substantial time using digital technologies, especially smartphones. Although smartphones are often considered a source of distraction, their widespread presence also provides an opportunity to integrate technology productively into the learning process. Teacher education programs, therefore, need to equip future educators with strategies to transform commonly used digital devices into effective educational tools. This study proposes a classroom-oriented approach in which smartphone-assisted, low-cost “pocket” experimental setups are used to demonstrate scientific concepts and enhance students’ involvement in science learning.

Methods:
The proposed activity utilizes a compact experimental setup suitable for classroom demonstration and student participation. A simple droplet-based apparatus is used to measure the surface tension of liquids, which, in turn, helps estimate the concentration of dissolved impurities in water. The method can serve as an alternative or complementary approach to conventional polarimetry, which is mainly limited to optically active solutions. In this experiment, droplets produced from a burette or syringe are recorded using a smartphone camera, and droplet formation and detachment are analyzed through video-based visualization techniques. The recorded data enable estimation of droplet parameters and facilitate discussion of key theoretical concepts such as surface tension, density, viscosity, gravitational acceleration, and Reynolds number. Visual analysis tools assist students in observing and interpreting experimental phenomena more effectively.

Results:
Classroom implementation indicates that smartphone-assisted pocket experiments successfully combine theoretical explanations with real-time measurement and visualization. Students demonstrate increased interest and engagement when familiar technology is incorporated into experimental activities. The approach improves conceptual understanding and encourages curiosity, critical thinking, and creativity. For teacher trainees, the activity highlights how low-cost experimental strategies can be used to teach complex scientific concepts effectively, particularly in educational settings with limited laboratory infrastructure.