Have you ever wondered how many times you can fold a delicious crêpe without it flipping over? A new study reveals the fascinating physics behind crepe folding dynamics.

In a quest to uncover the nuances of this culinary art, a physicist from France explored this phenomenon. He discovered that a single key number can explain the folding limits.

Tom Marzin, a research student at Cornell University, was inspired during a trip to his hometown of Brittany, France, a region known for its crêpes. He observed that while simply folding the tip of a crêpe causes it to flip, further folds create a delicate balance of gravity and friction that keeps it stationary. What scientific principles govern this behavior?

Marzin turned his curiosity into a research project, and he plans to present his findings at the upcoming American Physical Society meeting on March 20 in Denver.

Unlike traditional studies focused on permanent origami-style folds, Marzin’s work delves into what he terms “soft creases,” a competition between the element of gravity and material elasticity.

To observe this fascinating competition, Marzin conducted an experiment using pancake pieces. By attaching a section to a tabletop, he measured the flex it experienced when the opposite end hung over the edge. He found that all behavior regarding crepe folding can be predicted based on a single value known as the elastic gravity length, which factors in material density, stiffness, and gravitational forces. Marzin speculates that this concept could apply to various flexible materials beyond just crêpes, supported by computer model simulations.

To test his theories in a practical setting, Marzin experimented with plastic discs, store-bought tortillas, and crêpes. Finding homemade crêpes unreliable for experiments due to thickness variability, he enlisted his mother to procure commercial crêpes that ensure consistent thickness.

Marzin’s experiments confirmed that all aspects of crêpe folding are dictated by this elastic gravity length. For instance, by controlling the folded area’s dimensions, one can determine if there’s sufficient surface area left for subsequent folds.

His equation accurately predicts that a crêpe measuring 26 centimeters in diameter and 0.9 millimeters thick can be folded up to four times. In contrast, a similarly sized tortilla at 1.5 millimeters thick, exhibiting an elastic gravity length of 3.4 times, can withstand just two folds. “This length encapsulates the essential physics,” Marzin concludes.