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It’s been a scientific fact so widely recognized that it’s taught in educational settings and reiterated in popular science videos: An egg is most robust when dropped straight down, on its ends. However, when MIT engineers actually examined this premise, they unveiled a surprising discovery.
Their investigations demonstrated that eggs dropped on their sides — instead of their tips — are significantly more durable, attributed to a clever physics principle: Sideways eggs flex like shock absorbers, exchanging rigidity for enhanced energy absorption. Their open-access results, published today in Communications Physics, not only revise the principles of the traditional egg drop challenge — they serve as a lesson in intellectual humility and inquisitiveness. Even “settled” science can disclose surprises when approached with meticulousness and an open mindset.
At first glance, an eggshell might appear delicate, but its durability is a wonder of physics. Break an egg on its side for your morning scrambled eggs and it shatters effortlessly. Intuitively, we think eggs are tougher to shatter when positioned upright. This belief has long been a foundation of the classic “egg drop challenge,” a favored scientific exercise in STEM classrooms nationwide that introduces pupils to physics topics around impact, force, kinetic energy, and engineering principles.
The yearly egg drop contest is a highlight of freshman orientation in the MIT Department of Civil and Environmental Engineering. “Each year we consult the scientific literature and discuss with the students how to place the egg to prevent breaking on impact,” says Tal Cohen, associate professor of civil and environmental engineering and mechanical engineering. “But about three years ago, we began to question whether vertical really is stronger.”
This inquisitiveness fueled an initial experiment by Cohen’s research team, which leads the department’s egg drop event. They decided to utilize their remaining crate of eggs for experiments in the lab. “We expected to validate the vertical position’s toughness based on what we had read online,” states Cohen. “Yet when we analyzed the data — it was quite ambiguous.”
What commenced as a casual inquiry transformed into a research endeavor. To thoroughly examine the durability of both egg orientations, the researchers performed two varieties of examinations: static compression tests, which applied gradually increasing pressure to assess stiffness and toughness; and dynamic drop tests, to quantify the likelihood of cracking upon impact.
“In the static testing, we aimed to hold an egg still and apply pressure until it cracked,” clarifies Avishai Jeselsohn, an undergraduate researcher and contributing author of the study. “We employed thin paper supports to accurately position the eggs vertically and horizontally.”
The researchers discovered that it took an equivalent amount of force to initiate a fracture in both positions. “However, we identified a significant difference in the amount the egg compressed before it ruptured,” says Joseph Bonavia, a PhD candidate who contributed to the project. “The horizontal egg compressed more under the same force, indicating it was more pliable.”
Using mechanical modeling and numerical simulations to corroborate their experimental findings, the researchers concluded that although the force to crack the egg was consistent, the horizontal eggs absorbed more energy thanks to their flexibility. “This indicated that in scenarios where energy absorption is crucial, such as during a drop, the horizontal orientation might be more durable. We then conducted dynamic drop tests to verify if this held true in practice,” states Jeselsohn.
The researchers established a drop setup using solenoids and 3D-printed supports, ensuring simultaneous release and consistent egg orientation. Eggs were dropped from varied heights to scrutinize breakage patterns. The outcome: Horizontal eggs cracked less often when dropped from the same altitude.
“This validated what we observed in the static tests,” notes Jeselsohn. “Although both orientations endured similar peak forces, the horizontal eggs absorbed energy more effectively and exhibited greater resistance to breaking.”
Questioning prevailing beliefs
The research uncovers a misunderstanding in popular science concerning the strength of an egg when subjected to impact. Even experienced researchers in fracture mechanics initially presumed that vertically oriented eggs would be stronger. “It’s a prevalent, accepted notion, cited in many online references,” observes Jeselsohn.
Everyday experiences may reinforce that misunderstanding. After all, we frequently crack eggs on their sides while cooking. “But that doesn’t equate to resisting impact,” elucidates Brendan Unikewicz, a PhD candidate and co-author of the paper. “Breaking an egg for cooking entails applying localized force for a clean break to retrieve the yolk, while the resistance to breaking from a drop involves distributing and absorbing energy throughout the shell.”
The nuance is subtle but significant. A vertically positioned egg, while stiffer, is more fragile under abrupt force. A horizontal egg, being more flexible, bends and absorbs energy over a greater distance — akin to how bending your knees during a fall softens the impact.
“In a sense, our legs are ‘weaker’ when bent, but they’re actually more effective in absorbing shocks,” Bonavia adds. “It’s the same with the egg. Toughness isn’t solely about withstanding force — it’s about how that force is dissipated.”
The research outcomes provide more than insight into egg dynamics — they highlight a broader scientific principle: that widely endorsed “truths” merit re-examination.
Which came first?
“It’s refreshing to witness an instance of ‘received wisdom’ being scientifically scrutinized and found to be incorrect. There are numerous such instances in scientific literature, and it poses a genuine challenge in some fields because securing funding to contest an existing, ‘well-known’ theory can be difficult,” comments David Taylor, emeritus professor in the Department of Mechanical, Manufacturing and Biomedical Engineering at Trinity College Dublin, who was not associated with the study.
The authors hope their findings motivate young individuals to maintain their curiosity and realize just how much remains to be uncovered in the physical realm.
“Our paper serves as a reminder of the importance of questioning common beliefs and relying on empirical data, rather than intuition,” states Cohen. “We aspire for our work to encourage students to remain inquisitive, challenge even the most familiar assumptions, and continue thinking critically about the physical environment around them. That’s our goal in our group — consistently contesting what we’re taught through thoughtful inquiry.”
In addition to Cohen, who acts as the senior author on the paper, co-authors comprise lead authors Antony Sutanto MEng ’24 and Suhib Abu-Qbeitah, a postdoctoral researcher at Tel Aviv University, along with the following MIT affiliates: Avishai Jeselsohn, an undergraduate in mechanical engineering; Brendan Unikewicz, a PhD candidate in mechanical engineering; Joseph Bonavia, a PhD candidate in mechanical engineering; Stephen Rudolph, a lab instructor in civil and environmental engineering; Hudson Borja da Rocha, an MIT postdoc in civil and environmental engineering; and Kiana Naghibzadeh, Engineering Excellence Postdoctoral Fellow in civil and environmental engineering. The research received funding from the U.S. Office of Naval Research with support from the U.S. National Science Foundation.
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