How Strong is an Egg Shell? Strength of Eggshell Bridge

Today, we are going to measure the strength of Egg Shells by building a Eggshell bridge.

I am going to prove these thin egg shells can hold multiple times their weight.

The secret lies in the eggshell nanostructure and its shape.   Let’s get into this amazing egg science experiment.

How Strong is an Egg Shell

Area of Science: Material Science

Time Required: Less than 10 mins provided you have the egg shells

Safety: Eggshells are the good source of bacteria, Salmonella. Hence, it is a good habit to wash the eggs before and after the experiment. Also if you or your child is allergic to egg vapor – take caution while doing this activity.

Age Group: Actually, this experiment can be done by any age group children. Younger kids can enjoy watching how eggshells are managing holding heavy weight through this great visual demonstration. Older kids can learn the simple science concepts behind this activity.

Objective: To check how strong is an eggshell and how much weight an eggshell can hold without giving any crack.

The experiment or activity on eggshells actually looks at how the outward brittle and weak nature of eggshells can actually hold heavy mass or load. It might happen only under certain conditions. Let us learn that secret of holding heavy items by building a bridge using half eggshells.

Materials Required

Things We Need

Let us see those magical ingredients:

1) At least four eggs (you can take more to be on safe side)

2) Scissors (sharp knife also helps to get the work done)

3) Heavy and light-weight Books

4) A Pen

5) A Bowl

6) Safety goggles, to protect your eyes from bits of egg shell 

That’s it! You are done with gathering supplies required for this awesome experiment.


Before you start the experiment, carefully break the eggs into a bowl by giving appropriate crack exactly in the middle such that we will get dome shaped and equal sized egg shells. Make use of egg fillings for conducting other investigations or just to make delicious dishes.

Now wash the emptied and dome shaped eggshells under fresh tap water and let them to dry completely. Then, try to trim the edges of the eggshells inner part using scissors to make them stand evenly on the smooth or flat surfaces. That’s it! Your eggshells are ready to go on to the experiment table for investigation.

How to make an eggshell Bridge?

Here is one of the best methods to build strong enough eggshell bridge using our dome shaped eggshells. All you need is four egg shells that are dome shaped.

Method to make Eggshell Bridge:

Using a sketch or color pencil, draw a fine line around the egg as evenly as possible and use this line as a guide to break the egg carefully in order to obtain a dome shaped egg shell after breaking. Children’s who are performing this experiment on their own can take the help of an adult to do this tricky step.

Simple Instructions to investigate the eggshells strength

Step-1: Arrange the dome shaped egg shells in a rectangular shape on a flat experiment table or you can use even the floor as the base so that the egg shells are prepared to hold your stack of books. Yes, we are using a stack of books as a heavy mass or weight to check how much weight the arranged egg shells can hold.

Arrange Eggshell

Step-2: First, place a single book on to the egg shells carefully. Once the first book balances perfectly on the eggshells, try to add one more book of same or different weight..

Arrange Books On Eggshell

Step-3: Keep adding books to the stack on to the egg shells one by one. (Extension: You can continue adding books one-by-one. When you add each time, record the weights of books that are being added)

Arrange Books On Eggshell GoScienceGirls

 Step-4: Eggshells mange bearing books weight as long as they can! See how you many books you can add to the eggshell bridge before the egg shells crack. This is also a little tricky step because before you realize the cracking on the egg shell, the heavy weight added may break the egg shell. So observe carefully while adding books to the stack on the egg shells.

Arrange 2nd Layer Eggshell

Optional: You can paint your egg shells before they go for investigation for testing their strength. Make a note: Slowly, the edges of the eggshells start chipping off into small pieces but there is nothing to worry. Because the eggshells are still able to manage weight. Let the set up leave until the eggshells broke off completely.

How Strong The Egg Shells

What actually is going on?

Eggs are easily cracked if they hit any hard surface because the shell of the eggs are fragile.

But how the egg shells in this experiment managed to hold the heavy weight!! Because the dome shaped egg shells provides strength and support a great deal of weight.

Amazing right! Let us get into the science in detail.

Increase Weight On Egg Shells

Usually, eggshells are found to have nanostructure. In addition, they are made up of calcium carbonate which is a “nature’s ceramic”. And they become very strong when they are compressed.

The compressed eggshells strength is similar to that of a bone. Sounds amazing huh!

What exactly happening here is: the weight forced on the eggshells is spread all over the circumference of the egg. 

The curved or dome shape of the egg shell is the main reason behind the spread of force towards outward direction.

As a result, the force applied on eggshell is spread vertically and horizontally but not straight.

Increase Egg Shell Layer

We see domes and arches used in constructing bridges, houses, roofs, tunnels, underground drainages, igloos, etc.

And while constructing them, engineers apply the same science as of eggshell strength. Here the curve shape of the domes and arches plays the hero role and distribute the weight and pressure evenly.

Egg Shell Broken
Broken Egg Shell
Weight Balanced On Egg Shell

Variables to test

1) You can try using eggs from different sources. For example: Duck eggs, chicken eggs, etc.

2) Find what other shapes are strong?

3) Check out which type of shapes that are used in buildings and other constructions proves strong?

Books On Eggshell

Key Questions

1) What is the exact number of books or books weight an eggshell can hold?

2) Does an eggshell manages to hold weight when the books are balanced on its sides?

3) Why are arches and domes so strong?


How strong is eggshell?

The egg shell is made up of calcium carbonate and weighs only about one-fifth of an ounce.

At right conditions, the thin layer of the egg allows an egg standing on end to bear a 130 pound weight without breaking.

Why are Eggshells so strong?

Basically, egg shells are composed of organic and inorganic material along with some abundant proteins and calcium-containing minerals.

The nanostructured egg provides the amazing strength to the egg shells associating with osteopontin.

Osteopontin is the multi-functional and versatile protein. In composition this protein matches to the bone protein and is mainly associated in metabolism of bones.

How much force an eggshell withstand?

The applied force and the amount of weight distributed by the egg shells decides the amount of force an eggshell can withstand.  Actually, to break an egg, it requires a little more than 5 ½ pounds of force.

What is the strongest part of an egg shell?

The strongest part of the eggshell lies at the top or bottom point of an egg. Therefore, an egg doesn’t break when you apply pressure at the peak points of both the ends.

Also, the curved shape of an oval shaped egg is the strongest part since it participates in distributing weight and force evenly through the entire structure.

Why are eggs so fragile?

Eggs break easily when certain amount of force is applied and in which direction the force is applied also matters. Hence, eggs can hold surprising and enough amount of force created by weight.

What are you waiting for? Grab some eggs from your kitchen and put them for some interesting investigation.

Leave a Reply

Your email address will not be published. Required fields are marked *