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Once a week we will be featuring an activity you can try at home or in the classroom. This week’s entry is written by Linda Meyers, with technical know-how and research provided by Liz Elmore, School Programs Intern at Heifer International.

If you have been reading the blog lately you have probably read how much a chicken or rabbit can do for a family in need. If you haven't, you'll want to check out a few of the posts, especially this one with an ultra-cool Easter infographic.

Eggs are definitely on our minds this time of year, so we thought it would be a great time to try this mind-bending eggs-periment that will surprise you with its amazing results.

Just how strong do you think an eggs is? To test the strength, try this eggs-tra eggs-iting eggs-periment:

You will need:

  • 4 eggs
  • A towel
  • A pile of books


  • Crack each egg in half. Put the yolks and whites in a container and store for future use. (Set the pointy half of the shells aside, and after the experiment, you can compost them along with the rest of the shells.)
  • Place a towel on a flat surface and position the eggs on top to make a square, with the dome side of the egg on top.
  • Add books one by one on top of the egg shells so that the weight is distributed evenly.

How many books do you think the eggs can hold before they crack?

Do you think egg shells can protect the insides of an egg?

Eggshell Strength Explained: Just like the Capitol building, eggs contain the shape of a dome.  Did you ever wonder how such a seemingly fragile object like an eggshell can protect the developing embryos of so many animals? In fact, the arched shape of the eggshell is seen in many types of architecture, including bridges and domed buildings. Not only are they architecturally pleasing, domes and arches are very strong, because f the  material they are made of, and their shape. The eggshell of a chicken is composed of layers of calcium carbonate reinforced by a protein matrix. The arched, dome shape of an eggshell can resist the pressure of heavy loads by distributing weight evenly along the structure of the egg. Compression is a force applied to the outside of an object that pushes toward the object’s center, while tension is a pulling, stretching force. Eggshells are tension-weak materials, but are strong in compression. This is why it is difficult to crush an egg by squeezing on its ends (compression forces), but will break when chicks peck from the inside of the egg (tension forces).  So how strong can an eggshell really be? One unbroken eggshell has held up a 200-pound person!

For this and other fun, educational experiments go to the Experiments page on our website.

Now that you know the true strength an egg shell, you may want to learn more about how eggs bring strength to the effort to stop hunger and poverty across the globe.



Linda Meyers

Linda Meyers, an Arkansas transplant originally from St. Louis, Mo., started working at Heifer International in 2011. She enjoys dragging her three children on nature hikes and snapping photos of them and everything around her. She has a bachelor’s degree in English has been “in the process” of writing the great American novel for 24 years.