The key to a successful egg drop experiment? Drop it on its side | Hacker News Reader

The key to a successful egg drop experiment? Drop it on its side

arstechnica.com

35 pointssamizdis25 comments

> 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.

I find it hard to extrapolate from this experimental setup to an egg drop competition. A ~1cm drop onto a hard surface is quite different from a ~10m drop in protective packaging.

I wonder if someone made a mistake with unit conversions... The next paragraph says:

> The results: over half of the eggs broke when dropped vertically from an 8-millimeter (31-inch) height

31 inches is 0.8m, not 8mm. Maybe they meant to say 0.8, 0.9, 1.0 meters? Strange.

Yet the image ("Experimental snapshots for vertical (top) and horizontal (bottom) egg drops.") definitely appears to show something closer to 8mm, assuming the black area is the table.

Edit: Reading the paper [1] it's definitely 8mm. The ArsTechnica writer screwed up the conversion to inches. Should be 0.31".

1. https://www.nature.com/articles/s42005-025-02087-0

However you try to pad it there will end up being a hot spot where either the force is maximal or the shell is thinnest. So I think it makes sense to do the unprotected tests to see what the failure mode is for the egg and then design for that.

The neck is the weak point in a car crash. So we design cars and airbags and child seats to account for that.

In high school physics I procrastinated until the night before our egg drop competition to finally address what I was going to do. I got a medium/large size plastic tupperware container (rigid plastic body with a rigid lid). I took a bag of cotton balls, stuffed them in there as tight as I could, put an empty cardboard toilet paper roll vertically in the center, with more cotton balls designed to go in said cardboard below and above the egg. Taped the lid shut. People laughed at my concoction, especially those that went to great efforts to design theirs. I even tossed mine in the air beforehand to test it, which gave me extreme confidence going into the 30 ft drop that I'd be fine. I was. I do not recall what side it landed on but obviously it bounced several hard times after hitting the ground.

i've done this experiment 2 years in a row with my youngest kiddo as a STEM challenge in elementary school. i thought we got pretty close this year with using heavy duty sponges, paper plates, and a parachute, but was always operating under the assumption that the egg needs to be vertical. i'm excited to try again next year after reading this.

oh and at our school, they bring in a big bucket truck from the local power company and send the teachers up to the top with the devices and let them drop them :)

Get a block of styrofoam, slice it in two, and carve out a hole between the blocks exactly the size and shape of your egg. Tape the blocks together with the egg in the centre.

It is incredibly effective to have a solid surface in contact with the whole shell. And, the outer styrofoam will absorb the worst of the landing. It's also very light, so it minimizes the energy that must be dissipated.

Lesson learned from my failed attempt at the egg drop in high school. The guy with the styrofoam absolutely destroyed everyone at that challenge.

Even simpler: A barrel of water densified such that the egg floats in the middle

That was the solution employed in the ActionLabs video linked in another comment, but you'll note that their first attempt failed with that approach.

It's difficult to prevent any container that heavy from breaking open when hitting concrete at terminal velocity. I'd bet that the styrofoam block could be dropped from any height and survive landing on any surface, no matter how unyielding.

How about soaking the egg into epoxy resin ?

That cracks me up!

Even if the egg doesn’t survive, nobody will ever know!

The one time I did it in highschool I suspended the egg in a small cloth bag within a box. No padding just the secure cloth bag attached to the inside corners of the box with taut twine. Egg survived the 3 story drop easily, even was fine when we kicked it around afterwards.

Yeah, I carefully followed the rules on that competition and made a cage that had the egg suspended with rubber bands. Worked pretty well in home testing. Lost to the kids that shoved wadded up paper towels into Tupperware containers.

Never believed in physics again.

Yeah, tight packing is simple and very effective. I had a successful drop with nothing but corn starch packing peanuts shoved into a cardboard box.

I put it in a half filled gallon ziploc of flour (on top of the flour).

> They dropped 60 eggs each from three different heights (8, 9, and 10 millimeters)

Based on the photos, they measured this as the distance from the surface of the edge to the surface they were dropping it onto.

But for the vertical egg drop, the center of mass is several millimeters higher than for the horizontal drop, a pretty significant difference when you're only dropping 10mm at the most.

Maybe I'm missing something, but based on how they set up the experiment, maybe they're not measuring how resistant the egg is in certain positions, but instead just measuring that higher potential energy is more likely to break an egg?

Unless the egg rotates significantly during the fall, the distance from the floor to the bottom surface of the egg determines the potential energy that could go into falling speed before the egg hits the floor. In order to fall further, the egg either needs to have already cracked or to roll once hitting the floor (unlikely to cause cracking if the initial impact didn't).

> over half of the eggs broke when dropped vertically from an 8-millimeter (31-inch) height

Something went wrong with the units I think

8mm is a bit under a third of an inch (25.4mm), so someone dropped the decimal point.

I think they meant 8 meters as they showed someone dropping eggs from a bucket truck.

They mention the eggs cracking a middling fraction of the time.

Just now, dropping an egg about a finger-width onto whatever my kitchen counter is made of did indeed leave a small crack, so part is an inch is about right.

https://xkcd.com/3065

From an engineering standpoint it ‘makes sense’ to make the device radially symmetrical by standing the egg on one end. But it sounds like that causes the device to need to be better to achieve the same level of protection.

Isn't this simply due to the fact that there's more surface area contact when an egg is on it's side vs vertically.

I thought the key was to completely surround it with water & make sure it's not floating next to any side of the container to avoid incidental contact.

https://www.youtube.com/watch?v=JBo9X2Hkw1s

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