Standing on Eggs

Eggshells are surprisingly strong if they are compressed. The curved shape of the eggshell allows the force of your weight to be spread horizontally and vertically throughout the entire shell, rather than focusing the pressure on a single point where it would crack.

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 because they effectively channel weight into the ground or the supporting structure. Some structures built by the ancient Romans have survived thousands of years due to arches built into their design, proving just how much weight this shape can support!

Road safety application

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

Curved surfaces also distribute forces in cars. Modern cars are designed with crumple zones that work in a similar way to bike helmets. These zones are engineered to deform during a crash, soaking up the massive impact forces so that the energy doesn’t reach the people inside the vehicle.

Variables to test

Find out more on variables here.

• Efficiency
  Is there a way to arrange the eggs so that you can use fewer of them and they still survive the weight?
• Alternative Materials
  Can this be done with balloons? What about water balloons? Does the internal pressure of the balloon change the “arch” strength?
• Orientation
  Does it matter if the eggs are on their side or upside-down? Does the “pointy” end of the egg provide more or less stability than the wider end?

Going further

Try testing exactly how strong eggshells are with this activity! By using just the shells, you can see how the dome shape alone can support stacks of heavy books.