Simple, low-cost method measures thermal diffusivity of food

Heat transfer and exchange are important physical phenomena that should be considered when defining a material’s thermal properties and subsequent applications. Wang et al. accurately determined the thermal diffusivity of a wide variety of food samples using common tools and simple methods.

“Cooking is a tangible, familiar, and delicious tool for learning physics, both in science concepts and the scientific research process,” said author Jim Wang, the scientific advisor to two high school students leading the project.

Foods, such as sweet potato, pumpkin, radish, eggplant, and onion, were formed into spheres using a regular kitchen vegetable peeler. These foods naturally offered experimental variations in diameters and densities.

The thermal diffusivity of each food was determined by suspending and immersing the samples in boiling water. The center temperature increase of each sample was tracked as a function of time.

By using a simple sample preparation method and an inexpensive thermocouple, the team created a method that could easily be implemented in university teaching laboratories. Additionally, since the results followed simple scaling laws, students can discover for themselves the factors that govern heat conduction.

The measurement data and simulated results were in good agreement, and the technique could be generalized to a wide variety of samples.

“We hope our work can stimulate more interest in studying culinary sciences,” said Wang. “Our method can be applied to measure thermal diffusivity for many other types of foods and food mixtures.”

Source: “A simple and low-cost experimental method to determine the thermal diffusivity of various types of foods,” by Lisa R. Wang, Yifei “Jenny” Jin, and Jian Jim Wang, American Journal of Physics (2002). The article can be accessed at https://doi.org/10.1119/5.0087135 .