Did You Know?
Thomas Edison was a very curious child. It is said that he observed a goose sitting on her eggs, and his mother explained that the hen was keeping the eggs warm so they would hatch. Soon after this Mrs. Edison became concerned about the absense of young Thomas. She found Thomas fast asleep on a nest of goose eggs. Thomas had decided that he would warm the eggs himself. There is no mention of whether the weight of the young boy broke the eggs or not. But, it is entirely possible that the eggs were not damaged. This is because of the shape of the eggs.
As the video below will reveal, the dome shape of eggs makes them very strong. Birds of all sizes and weights are able to sit on their eggs without cracking them. A dome is a three-dimensional arch, which is one of the strongest architectural forms.
Eggs have a dome shape on each end. One end is more pointed than the other, this end is the strongest part. The sharper the curve of a dome, the stronger and more rigid it is at its tip. The shape of the arch distributes forces. Domes have no angels, no corners.
In any structure there are always two types of forces at work–compression and tension. When designing and building structures, architects and engineers must consider these two forces: Tension and Compression. 
The diagrams show two easy ways to demonstrate the difference in the direction of compression forces and tension forces. Structural engineering is the branch of engineering concerned with the design and construction of all types of structures, including bridges, dams, tunnels, power plants, and space satellites.
Find out more about structural engineering as well as other engineering careers in Engineering for Every Kid.
