Recent experiments have highlighted a notable distinction in how eggs, when squeezed either vertically or horizontally, respond to compression. The study revealed that vertically positioned eggs experience less deformation compared to their horizontally held counterparts. This difference can be attributed to the greater rigidity of the egg’s shell along its length, enabling the distribution of weight more evenly across its surface. This principle is evident in the popular one-handed technique for cracking eggs, which targets the center of an egg held horizontally.
However, the study’s findings indicate that this advantage in static compression turns into a liability when eggs are dropped from heights. The horizontal orientation appeared to be the most effective position for withstanding impacts. This discrepancy arises from the distinction between stiffness—which refers to the force required to deform the egg—and toughness, which describes the energy it can absorb before breaking.
Research conducted by Cohen et al. demonstrated that eggs display increased toughness when positioned horizontally along their equator. Conversely, they exhibit greater stiffness when subjected to vertical compression. The authors suggested that “an egg dropped on its equator can likely sustain greater drop heights without cracking.” They noted that although vertically loaded eggs might handle higher forces, this does not inherently mean they are less susceptible to breaking in that position. Unlike static loading, to avoid breaking upon impact, an object must effectively absorb its kinetic energy through reversible deformation.
The researchers concluded that “eggs need to be tough, not stiff, in order to survive a fall.” They drew parallels with human behavior, emphasizing that just as people instinctively bend their knees rather than keeping them straight when landing from a jump, eggs too must possess the right properties to endure drops. Moreover, they warned that the language used to describe such phenomena can influence our understanding of the mechanics involved. Misinterpretation due to the framing of concepts can lead to misunderstandings and educational shortcomings.
DOI: Communications Physics, 2025. 10.1038/s42005-025-02087-0 (About DOIs).
