Study reveals the best way to drop an egg without breaking it
The classic egg drop science experiment has gotten a big update, thanks to a new study.
Scientists from the Massachusetts Institute of Technology studied the best way to drop a chicken egg to prevent it from cracking – vertically, or on the side. Now, we may finally have an answer.
"Eggs are less likely to crack when dropped on their side than when dropped vertically," according to a new study published May 8 in the peer-reviewed journal Communications Physics.
What is the 'egg drop challenge'?
The goal of the ‘egg drop challenge’ is for students to prevent an egg from cracking when dropped from a given height (often they are asked to build devices to cushion the egg's fall as part of the experiment).
A common belief is that an egg is stronger and less likely to crack when dropped vertically, with this assumption often seen in teaching guidance from schools and among popular science communicators, according to a statement from the journal.
Why does this belief persist? Study authors write that "this idea appears to be based on an appeal to common wisdom, often inspired by the enduring design of structural arches and domes from ancient civilizations to the present day."
180 egg drop tests
Tal Cohen, an MIT associate professor, and her colleagues conducted a series of 180 drop tests to compare how chicken eggs break when orientated vertically or side-on. After dropping 60 eggs from each of three different heights — 8, 9, and 10 millimeters — onto a hard surface, the authors saw that, on average, eggs dropped vertically broke at lower drop heights.
More than half of the eggs dropped vertically from 8 millimeters cracked, with which end of the egg pointed downwards making no difference, the study found.
However, less than 10% of horizontally-dropped eggs cracked from the same height.
Compression tests also performed
An additional 60 eggs were subjected to compression tests, which measured the force required to crack the eggs vertically and horizontally. While 45 newtons of force was required to break the eggs in both orientations, the horizontally-loaded eggs could compress further before cracking.
The authors suggest that this means that "eggs are more flexible around their equator, and therefore able to absorb more energy in this orientation before breaking," according to the journal statement.
The authors conclude that the reason behind the common misassumption that an egg dropped vertically is less likely to crack is a confusion between the physical properties stiffness, strength, and toughness.
According to the study, eggs are stiffer when compressed vertically, but the authors say that this does not necessarily mean that eggs are also tougher in that direction. The authors also suggest that future research could explore the application of these findings to engineering scenarios, such as how structures respond to dynamic loads.
Why perform the experiment?
The study notes that "ideas about the strength of shells have implications beyond the chicken egg. In nature, shell structures are ubiquitous, serving as a protective layers for soft-bodied organisms; turtle shells and sea shells, to human skulls, and even the outer membranes of viruses and bacteria.
"Insights on the mechanical failure of these structures may thus enable progress in a myriad of applications ranging from the design of protective equipment to drug delivery."