The Science of Chocolate: Interactive Activities on Phase Transitions, Emulsification, and Nucleation

Abstract

Nearly everyone loves chocolate, which makes this an excellent topic for communicating scientific concepts to the general public and to students in the classroom. Here we present the outline and activities for an interactive presentation on the science of chocolate for nonspecialists and their children ages 6 and up. We design the presentation around three major questions related to observable properties of chocolate: Why does chocolate melt in your mouth, not in your hand? Why does chocolate feel smooth in your mouth? Why does chocolate look glossy and snap when you break it? To address these questions, we lead the audience through a series of taste experiments, and use a combination of live demonstrations and interactive activities with children. The general approach can be adapted to a variety of informal and classroom settings focused on sharing the excitement of scientific understanding with students and the public.

The molecules we eat: Food as a medium to communicate science

“…To demonstrate phase transitions and the effect of molecular composition on phase behavior, a popular taste test involves comparing milk and dark chocolates. Such a gustatory method also requires that individual audience members become scientists as they make observations of chocolate texture and flavor, while learning of the underlying scientific basis of these physical properties [7]. In a lecture on diffusion, taste tests of tofu marinated in soya sauce for 2 versus 24 hour intervals provide unforgettable experiences of the time and length scales of diffusion.…”

“…Lecithin is also an effective emulsifier that is commonly added to chocolate (Figure 1), as well as other foods. Starting with the simple task of deciphering ingredient labels [7,16], scientists can play an important role in promoting scientific literacy and dispelling fear of molecules.…”

The emerging science of gastrophysics and its application to the algal cuisine

“…In recent years, the collaboration between famous chefs and scientists has materialized in cookbooks that contain a significant element of scientific explanations, such as Heston Blumenthal's The Fat Duck Cookbook [20], and books that focus on the science of particular types of food, such as the science of ice cream [21], chocolate [22,23], pizza [24] and sushi [25]. The most recent development in writing on the science of cooking is embodied in the monumental five-volume tome by Nathan Myhrvold and colleagues on what is called 'Modernist Cuisine' [26].…”

How Study of Chocolate as a Material Can Be Used to Enhance Engineering Education

“…The desirable form of the cocoa butter is form V, which has a melting temperature between 90-94 o F and the associated properties of good chocolate. 3,5,6,7 A useful activity to do is to have students work with form V cocoa butter and form IV cocoa butter to test the "snap" and the hardness (using Shore Durometer) of the different forms. The form V cocoa butter is in purchased dark chocolate, which is readily available.…”