The key to a successful egg drop experiment? Drop it on its side
Eggs are less likely to crack when dropped horizontally vs. vertically, contradicting conventional wisdom.
Egg drop competitions are a staple of high school and college physics classes. The goal is for students to build a device using bubble wrap, straws, or various other materials designed to hold an egg and keep it intact after being dropped from a substantial height—say, ten meters (nearly 33 feet). There’s even a “naked egg” version in which a raw egg is dropped into a container below. The competition is intended to teach students about structural mechanics and impact physics, and it is not an easy feat; most of the dropped eggs break.
MIT engineering professor Tal Cohen decided to investigate why the failure rate was so high and reported her team’s findings in a paper published in the journal Communications Physics. “The universal convention is that the egg should be in a vertical orientation when it hits the ground,” Cohen told Physics Magazine. But their results from controlled trials simulating the egg drop challenge in the lab calls this conventional wisdom into question.
It is not an unreasonable assumption to make. Another popular physics party trick is to walk on several cartons of eggs without breaking them. Typically it only takes about five and a half pounds of force to crack a single eggshell, much less than the average adult human. As I wrote for Slate back in 2012, “The key is to align the eggs so that the narrow pole is pointing upward, and step in such a way to distribute your weight over the entire surface area, to avoid overloading any one eggshell.” (Being barefoot also helps.)
In fact, I noted at the time a surprisingly long history of scientific studies of eggshells and how cracks propagate, particularly in the 1950s and 1960s, when they served as useful models for failure analysis when building airplanes. The toughness comes from the egg shell’s structure; it is made up mostly of calcium carbonate (calcite) crystals, similar to tooth enamel or sea shells, embedded within a protein matrix. The egg shell is strengthened further by a thin inner collagen layer. This tends to keep damage localized as cracks spread little by little rather than one clean break.
Cohen et al. give a shoutout in their introduction to Jonathan Swift’s Gulliver’s Travels, specifically the longstanding quarrel between the people of Lilliput and Blefuscu on the best orientation for cracking an egg. Of course, there is the classic chef’s one-handed egg-cracking technique—immortalized in the 1954 romantic comedy, Sabrina—which involves holding the egg between the fingers and thumb and rapping the edge sharply against the rim of the bowl to achieve a clean break. Alas, this usually ends in a crushed eggy mess when attempted by amateurs. (Practicing with a golf ball can improve one’s skill.)
MIT scientists have previously studied precisely how much force to apply to the center of an egg. Specifically, the scientists devised a mathematical formula linking the ovoid geometry of the eggshell and its rigidity—a property that, along with strength (a related but distinct concept), accounts for how much force a given object can withstand before breaking. It’s the narrow tip that is the most crack-resistant part of the egg, since the shell becomes more rigid the more the egg curves. That’s why pressing down on both the bottom and top of an egg with your fingers won’t work. But turn the egg horizontally and press right at the center, and the shell cracks easily.
Stiffness vs. toughness
So what’s going on with these latest MIT findings? To find out, Cohen et al. bought 180 chicken eggs—Costco’s Kirkland Signature brand— and conducted their own egg drop experiments in the lab. They dropped 60 eggs each from three different heights (8, 9, and 10 millimeters) onto a hard surface in three different orientations: horizontal, vertical on the sharp end, and vertical on the blunt end. They also subjected an additional 60 eggs to compression tests to determine the force required to break the eggs in both the vertical and horizontal orientations.
Experimental snapshots for vertical (top) and horizontal (bottom) egg drops.
Credit:
A. Sutanto et al., 2025
The results: over half of the eggs broke when dropped vertically from an 8-millimeter (31-inch) height, regardless of which end of the egg was pointing downwards. Yet less than ten percent of the horiztonally-dropped eggs broke. The eggs broke when the force exceeded 45 Newtons, an impressive per-egg load bearing capacity that is independent of its orientation.
There was a key difference, however, between how vertically and horizontally squeezed eggs deformed in the compression experiments—namely, the former deformed less than the latter. The shell’s greater rigidity along its long axis was an advantage because the heavy load was distributed over the surface. (It’s why the one-handed egg-cracking technique targets the center of a horizontally held egg.)
But the authors found that this advantage when under static compression proved to be a disadvantage when dropping eggs from a height, with the horizontal position emerging as the optimal orientation. It comes down to the difference between stiffness—how much force is needed to deform the egg—and toughness, i.e., how much energy the egg can absorb before it cracks.
Cohen et al.’s experiments showed that eggs are tougher when loaded horizontally along their equator, and stiffer when compressed vertically, suggesting that “an egg dropped on its equator can likely sustain greater drop heights without cracking,” they wrote. “Even if eggs could sustain a higher force when loaded in the vertical direction, it does not necessarily imply that they are less likely to break when dropped in that orientation. In contrast to static loading, to remain intact following a dynamic impact, a body must be able to absorb all of its kinetic energy by transferring it into reversible deformation.”
“Eggs need to be tough, not stiff, in order to survive a fall,” Cohen et al. concluded, pointing to our intuitive understanding that we should bend our knees rather than lock them into a straightened position when landing after a jump, for example. “Our results and analysis serve as a cautionary tale about how language can affect our understanding of a system, and improper framing of a problem can lead to misunderstanding and miseducation.”
DOI: Communications Physics, 2025. 10.1038/s42005-025-02087-0 (About DOIs).
Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.
