The exterior structure of the egg capsule can be built from any materials on the approved list. Some students construct a simple box filled with impact-absorbing materials such as packing peanuts or open-cell foam rubber. The simple containers are lighter, but may not afford the precious cargo with adequate protection. Consequently, students have to think through the design specifications of their project. A lightweight, rigid capsule will transfer the impact of the fall to the contents, while a heavier capsule could be engineered to include shock absorbing characteristics, such as a foam rubber coating. Because the capsules must be constructed from a list of approved materials, all the students start on a level playing field.
At the beginning of the competition, the judges insert the eggs into the internal egg cradle. For this reason, students must plan in advance and their egg cradle must be accessible on the day of the competition. Students cannot wrap the eggs ahead of time and create a capsule which resembles a ball of yarn, or the inside of a baseball. Students must think through the physics of the experiment and devise a way to absorb the impact without transferring the force to the eggs.
One approach involves constructing the egg cradle inside the capsule that doesn't move, but absorbs the impact. By filling the inside of the capsule with material such as Styrofoam peanuts, or crumbled newspaper, students can attempt to create a lightweight device which absorbs the shock without breaking the eggs. This approach challenges students to invent a methodology which absorbs the high amount of force with which the egg capsule hits the ground.
A second approach to protect the precious egg cargo is to create a cradle in the device which suspends the eggs in the middle of an open space on elastic hammock. Using this approach, students plan to allow a cradle to move about inside the capsule when it impacts the ground. Rather than trying to shield the eggs and absorb the force of impact, students use an engineering principle commonly employed in automobile engineering called a crumple zone. The cargo is protected by redirecting the impact forces away from the eggs while allowing the eggs to move about as the forces are dissipated.