Abstract: Sublimation is a critical step in the extraction of caffeine from tea leaves. In traditional methods, this process occurs within an evaporating dish, which limits students’ ability to visually monitor the entire sublimation process during heating. Additionally, the difficulty in controlling the heating temperature can lead to various issues: some students may not initiate sublimation due to insufficient heat, while others may inadvertently cause colored impurities to sublime alongside the desired product, or even result in carbonization when the temperature is excessively high. This study introduces the use of glassware in place of evaporating dishes, allowing students to clearly observe the phenomena associated with sublimation. Furthermore, temperature-sensitive test papers are employed to identify the optimal sublimation temperature. The integration of “visualization” in this context not only aids students in observing and documenting experimental phenomena, but also establishes a connection between these observations and sublimation temperature. More importantly, it fosters students’ ability to integrate theoretical knowledge with practical application, thereby enhancing their problem-solving skills.

Key words: Caffeine, Sublimation, Temperature sensitive test paper, Visualization