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Comment by powercf | Hacker News Reader

I think the egg-drop challenge example is terrible. If the egg + protection impacts the ground at a fixed velocity, the most relevant factor is the /distance/ the egg moves before coming to a stop. So if it requires "three feet of bubblewrap" (nonsense number, per the video), then it will also require three feet of microlattice, unless the microlattice applies a more constant force on the egg as it compresses.

Bad examples like that make it difficult for me to trust such videos.

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A secret of the egg drop is actually that the egg doesn't really need much cushion to spread the impact over time. If you can spread the pressure evenly and hold it still, you can get away with quite a small crumple zone.

Carve a perfectly egg-shaped hole into a pair of styrofoam bricks, then tape them together with the egg inside. You'll beat 99% of the other kids who were trying to protect their egg with soft materials.

Source: I tried using wet sponges and carpet underlay, but was soundly beaten by a kid who carved a hole in a pair of styrofoam bricks.

What about suspending the egg in a jar of water?

Water doesn't compress as far as I know, so it would be like the egg hitting concrete...

water also distributes pressure uniformly, so it will be like trying to crush the egg pressing all the surface points of it with the same force. Which is not easy to do.

I once did the egg drop with a plastic container of honey. The container shattered and got honey everywhere, but the egg survived.

We should do this for egg drops on the moon. One time containers filled with honey.

So it is a good idea?

It's still a fluid though, so applying a force doesn't necessarily compress it. Think about dropping an egg into water.

I wonder if you could convert all the deceleration into compression using water though.

I dropped an egg in a shoe box full of sand and it worked fine. Unfortunately, that design wasn't allowed at my school.

Same principle - putting egg in a plastic jar of peanut butter works too. Provided the plastic jar is lightly padded. It takes a lot less padding to project the plastic jar than a naked egg and the viscosity of the peanut butter means that the egg won't drift from the center of jar.

I thought the canonical solution was also the cone-onical solution har har har.

https://youtu.be/wm2xC-EYBrc

With my first kid we used a small coontainer filled with a non-newtonian fluid. Worked like a charm. The following year we went for a paper cone with impeller blades fabricated along the top edge to make it spin and slow it down a bit.

We had a egg toss challenge. And were handily beaten by the group that duct-taped their egg inside a Nerf™ football and thrown by their team's quarterback. It was the uniform support of the shell by the Nerf material that did it.

I won my physics class egg drop challenge and three years of California MESA competitions in high school using spray insulation foam to make molds of specific eggs.

The MESA rules were 14" diameter max, no liquids, no parachutes, dropped from 60'. I cut a pattern of holes in cardboard and sprayed the foam over the eggs (lubricated with PAM), pulled the cardboard off, lubed them up on that side, and sprayed the other side. I trimmed the whole container to a sphere a little over 14" diameter and then compressed it as much as I could (Literally having someone stand on top of it) and wrapped it tightly in tape.

My best record using this method was 32 eggs with 100% survival.

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