Eggshells are very strong if they are compressed. The curved shape of the eggshell allows the force to be spread horizontally and vertically throughout the shell.

You can think of an eggshell as being like a 360-degree arched bridge. Engineers have known about the strength of arches for thousands of years. Arches are very stable and allow building structures to support a lot of weight. Some structures built by the ancient Romans have survived thousands of years due to arches built into their design.

Road safety application

Bike helmet curved surfaces help to distribute forces around the skull rather than directly onto the skull during a bike crash. However, it’s not just about the ability to distribute force in a bike helmet that protects you, its also the ability of the foam within the bike helmet to crumple and absorb the impact energy experienced when colliding with the ground.

Curved surfaces also distribute forces in cars and in a similar way to bike helmets, modern cars have crumple zones designed to absorb the impact forces experienced during a car crash.

Variables to test

More on variables here

• Is there a way to arrange the eggs so that you can use less of them and they still survive?
• Can this be done with balloons? What about water balloons?
• Does it matter if the eggs are on their side or upside-down?

Going further

Try testing how strong eggshells are with this activity