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How Strong is an Eggshell?


How Strong is an Eggshell?

This week we’re going to have a little fun! Growing up, I loved science fair projects. They were an awesome time to learn something new, be creative, and have fun. This week, we’re going to talk about how strong eggshells are.


I know what you’re thinking. “Annie, I barely tap my eggshells and they crack!”. While eggshells are fairly brittle and seem to crack easily, they are surprisingly strong. So, I set out to do a little experiment of my own to see what all the hype is about.


Eggs are fascinating to me. Their shells are porous and fragile, so why will they hold weight? The secret is actually their dome shape. When weight is placed on the dome, the weight is spread evenly throughout the eggshell. That way there isn’t one heavier point of load. Arches and domes are used in many forms of architecture including bridges, roofs, and even igloos! When you place a weighted object on the top of the dome, it spreads out to the outer edges, therefore, spreading the weight out evenly.


What You Will Need:

  • 4-6 eggs of the same size

  • Pen or pencil

  • Scissors or sharp knife

  • Books of different weights

  • Optional: kitchen scale

Step 1:

The first and most complicated step for this experiment is to carefully crack the eggs and shape the domes so they are fairly similar in height. Use a pen or pencil and draw a line around the middle of the egg. Carefully crack or score around the egg with your sharp knife or scissors. This step takes the most time, but it’s worth it to do it right.


Step 2:

Wash the eggs out. Use the insides to make a nice side of scrambled eggs! Let the shells dry completely. Finish trimming around the base of your “dome”.

How Strong is an Eggshell?

Step 3:

Make a base out of your 4 eggshell domes.


Step 4:

Weight your books one at a time and record your data.

How Strong is an Eggshell?

The eggshells easily supported these books, weighing in at 8lbs!


Step 5:

Carefully place the books, one at a time, onto the eggshell dome base.

How Strong is an Eggshell?

When I added a 3 lb. book, the eggs held for a couple seconds and then cracked. This would have brought the weight up to 11 lbs. and I think it would have held more if I had spent more time on the base of the domes.


Observations:

Some of my observations were this - It’s hard to make even eggshell domes! Haha! But, once I got fairly close, I went for it. Towards the end of the experiment, I could hear the eggs slowly start to crack. Take a little peek at your shells and see if you can see any fine cracks. I placed the heaviest book last and I wish I would have placed it first. My eggshells held nearly 8 lbs.!! Now, if you take into consideration that eggshells weigh approximately ⅕ of an ounce, that is a LOT of weight!


Things I’d Do Different:

If I do this experiment again, I will take more time to make sure my domes are a little more even. I’d also like to test out duck, geese and chicken eggs to see which is stronger.


Wow! This brought me back to 6th grade science! It’s honestly a fun project and maybe a great idea for your child’s science fair. Remember, it’s important to wash your hands before and after handling eggs!


Now if you’ll excuse me, I have some scrambled eggs waiting for me! Yum!


Until next time,


–The Wing Lady


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