Tempering chocolate as an activity to explore fundamental physics principles

Physics is often perceived by non-physics students as abstract and challenging, with concepts that can seem disconnected from everyday experiences. To make these concepts more accessible, food science can serve as an effective medium for introducing fundamental principles of physics and materials science. An Introduction to Biophysics course was developed and taught at Jefferson University in Fall 2020 and Spring 2024 with this goal in mind. The course offers students the opportunity to explore key physics concepts through biological systems, making the material more relatable and engaging.

A major component of the course involves using Visual Molecular Dynamics (VMD) software to simulate protein folding, biomolecular interactions, and energy landscapes. Additionally, a new module was introduced around the process of tempering chocolate, which provides a tangible way to explore complex topics such as entropy, crystal formation, nanoscale growth, and the various crystal phases of materials.

Cocoa butter, one of the main components of chocolate, has six distinct crystal phases. Properly tempered chocolate predominantly contains cocoa butter in the Phase V configuration, which imparts desirable qualities such as a smooth texture, a satisfying "snap," a higher melting point, and increased optical reflectivity. Students were highly motivated to achieve the ideal temper in their chocolate, allowing them to test their final products for sensory qualities like taste and mouthfeel. Using a scanning electron microscopy (SEM), students observed and measured the cocoa butter crystals, directly linking the microscopic structures they observed to the macroscopic properties of tempered and untempered chocolate. This hands-on approach helped students grasp challenging concepts and see the real-world applications of the physics principles they learned.