The egg drop challenge is an annual rite of passage for many students learning about physics: Swaddle an egg in cotton balls and masking tape or other materials, and then drop it off the roof of your school. Anyone who has participated in this exercise knows how difficult it is to engineer a structure that will save the egg from a messy end. (It certainly was not my bespoke foam core creation in middle school.)

Once the eggs are broken, teachers may reveal insights into the physics of impact, including the claim that eggs sitting vertically crack less often than eggs sitting horizontally.

But is that really true?

After running egg drop challenges for university freshman, Tal Cohen, an engineering professor at the Massachusetts Institute of Technology, began to wonder whether that assertion really fit the picture of a falling egg.

“It’s based on the static behavior of an egg,” she said. “Dynamic impact is quite different.”

To assess whether she was telling students the right story, she headed to the lab, eggs in tow, and performed some tests. What she found suggested the truth was more complicated, and in a paper out Thursday in the journal Communications Physics, she and her colleagues report that eggs lying horizontally are actually less likely to crack.

To perform their experiments, the researchers first headed to Costco and picked up more than 200 eggs (this at a moment in 2023 when eggs were cheaper than today). Then the team crushed some in a device that allowed them to record the force required to crack the shells. They found that eggshells cracked under about the same force regardless of whether they were lying down or sitting up in the device.

They then actually dropped the eggs. For experimental purposes, they dropped them from tiny heights — just eight millimeters or so. That was so they could see a variety of outcomes. If they dropped the eggs from bigger heights, all of them broke regardless of orientation.