How Strong Are Eggshells?

on June 28, 2013

Have you ever dropped an egg on the floor and broken it? Sometimes it seems like eggshells aren’t very strong, but that isn’t the case! Eggs can absorb a fair amount of weight when positioned correctly.

God designed the egg in an amazing way. They are fragile on the sides, where a chick needs to peck the egg to get out, but they are hard to break when applying pressure to the two rounded ends. This is why a nesting chicken can lay on an egg without breaking it.

You can observe this yourself by holding an egg over the sink (ask an adult for help). Position the egg so that you are pressing the two rounded ends between your palms, and apply pressure. If done correctly, it will be hard to break the egg. What happens when you position the sides of the eggs between your palms and apply the same pressure?

The design of the egg allows force applied to its ends to be evenly distributed, which improves its strength. Some architectural structures, like arches and domes, imitate this design so that they are stronger. This is an example of biomimicry, which is improving technology by imitating designs found in nature.

Perform the following experiments to discover just how strong eggshells can be.1 Don’t forget to ask an adult for help.

See For Yourself . . .

Because weight is distributed evenly, the dome shape of the eggshell can support a significant load. Try this simple experiment to test its toughness. (Adults should supervise the experiment and perform all cutting.)

Materials

  • 4 eggs
  • Painter’s tape or masking tape
  • Sharp scissors with a pointed end
  • Several large books (such as textbooks or dictionaries)
  • Towel
  • Bathroom scale
Egg Experiment

Step 1—Prepare the Eggs

(A) Wrap tape around the middle of each egg. (The tape both prevents the eggshell from cracking while you cut it and helps to keep the edges smooth.) Poke a fairly large hole in the pointed (smaller) end of the eggs.

(B) Drain the contents of the eggs.

(C) Insert the scissors into the hole you made, and then carefully cut up toward the middle of the egg. Now make a horizontal cut around the middle of the eggshell. Discard the smaller end. Make sure that the edge of the remaining shell is as straight as possible and that it has no cracks. (Don’t peel off the tape because that could rip the shell.) Note: Make sure all the eggshell halves are as close in height as possible.

Step 2—Stack the Books

(D) Smooth the towel out on a flat surface. Place four eggshells on the towel, with the curved end up. Form a rectangular shape that’s slightly smaller than your largest book.

(E) Starting with the largest book, stack one at a time on your eggshells until one collapses.

Step 3—Weigh the Books

Weigh the books to see how much weight your eggshells held. (A boy or girl weighing up to 40 pounds [18 kg] could actually stand on the shells without breaking them, if the eggs were cut perfectly and the child’s weight were evenly distributed on the shells!)

[Editor’s Note: Adapted from an article by John UpChurch, “Experiment: Walking on Eggshells,” Answers, July–September 2011.]

Related Downloads

More Egg Experiments

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Footnotes

  1. John UpChurch, “Experiment: Walking on Eggshells,” Answers, July–September 2011, http://www.answersingenesis.org/evidence-for-creation/experiment-walking-on-eggshells/.