Wednesday, March 30, 2011

Learning Physics Through Molten Chocolate Cake

Imagine learning about the physics of heat transfer by baking your own molten chocolate cake in an abandoned chemistry laboratory. That's what students at Harvard University did last year in a course devoted to teaching science through cooking. One of the course's instructors gave an overview of the program at the 2011 APS March Meeting.


[This lecture, called "Heat, Temperature and Chocolate," is the fifth in the series available on YouTube.]

Several hundred people packed the room for the "Science of Cooking: Motivating the Study of Freshman Physics" talk given by Harvard's David Weitz.

In the course, students (who sometimes had no science background) learned about science through cooking in an unused Harvard chemistry lab that was turned into a "food lab." There, plates and cutting boards replaced petri dishes and test tubes.

Students baked molten chocolate cake during one lecture to get a better understanding of heat transfer. The students used equations for heat transfer for the diffusion of heat to calculate how long the cakes needed to be baked, filling in variables like volume of the batter, heat of the oven (initial temperature) and the desired temperature. They were also able to use this equation to calculate how long a Thanksgiving turkey should bake and then verify their results on the turkey's packaging.

"Showing an equation like that to non-science freshmen physicists - they got it, they understood it because we did the experiment," Weitz said.

World-class chefs, including a white House pastry chef, presented a lecture each week, usually focusing on one ingredient or kitchen technique to teach a scientific concept.

"Chocolate...it's a wonderful material," Weitz said of one of the many ingredients used. The students also learned about elasticity through steak and about viscosity through olive oil.

Though he didn't get into quantum or even Newtonian mechanics, Weiss said, he did form an entire course around soft-matter physics - the science of liquids, gels, granular materials (think salt) and more, something he said has been his dream.

"The students really learned how to do science," Weitz said, by doing lab experiments based on cooking. And, from their reaction, they really seemed to enjoy it.

"I think the fact that you can eat the lab is really cool," one student said of the course in a video interview played during Weitz's talk.

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