The Egg Drop Challenge is a time-honored tradition for many physics students. Participants often wrap eggs in cotton balls, tape, and various materials before dropping them from a school rooftop. Anyone who’s taken part knows how challenging it can be to design a structure that keeps the eggs intact upon impact. (That wasn’t my finest creation back in middle school!)
After the eggs break, teachers often share insights about the physics involved, suggesting that eggs dropped vertically tend to crack less than those resting flat.
But is that really accurate?
Following her experience with the egg drop challenge, Tal Cohen, an engineering professor at MIT, began to question whether traditional claims about falling eggs held up under scrutiny.
“It relates to the static behavior of the egg,” she remarked. “The dynamics of the impact are quite different.”
To validate her hypothesis, she conducted tests in the lab with eggs. Her findings turned out to be more complex; Thursday’s paper in the journal Communications discusses how eggs resting horizontally are actually less prone to cracking.
To carry out their experiments, the research team procured over 200 eggs from Costco (an advantage when prices were lower in 2023). They employed devices to crush some eggs and measure the force necessary to crack the shell. Remarkably, they found that eggshells broke under similar forces, regardless of whether the eggs were horizontal or vertical.
Next, they actually dropped the eggs. For testing purposes, they dropped them from a modest height of about 8 mm, allowing them to observe varying outcomes. When dropped from a greater height, all the eggs broke, regardless of their orientation.
Significant differences in outcomes were noted. Eggs dropped on their sides were much less likely to crack. Upon landing, their shells could compress, absorbing some of the impact. Conversely, eggs landing on their ends exhibited more rigid shells with no similar flexibility.
Joseph E. Bonavia, a graduate student in engineering at MIT and co-author of the paper, noted this similarity to human physiology.
“When falling from a height, you want to avoid locking your knees, as that can lead to fractures,” he explained. “Instead, you bend your knees—much like the eggs do.”
The way we typically cook eggs may have contributed to the misconception that eggshells are most fragile, according to Brendan M. Uniquewicch, another MIT graduate student and co-author. We often break eggs at their midpoint, which results in a long crack that allows for clean separation. As these experiments illustrate, breaking at that point causes the shell to cave inward—an undesirable outcome for omelet-making.
Indeed, the experiments challenge our intuitions about how objects behave when they fall, Dr. Cohen noted. This highlights the importance for engineering students to remain open to questioning established beliefs.
Has anyone tasted one of these eggs? Due to university policy, researchers can’t consume experimental materials in the lab. However, Dr. Cohen’s dog enjoyed a hearty meal under such restrictions.
Source: www.nytimes.com
