Egg Shell Brown v.s. White
Aviva Mei
Sir Winston Churchill Secondary
Floor Location : J 154 D

This project looks at the difference in density between eggs with brown shells and eggs with white shells. When the egg is more dense, the egg is more fresh. This is because the air bubble at the bottom of the egg expands and therefore causes the density to decrease as the egg ages and becomes less fresh. My hypothesis was if I put an egg with white shell and an egg with brown shell both with the same initial density, mass and volume outside the refrigerator and inside the house in the same place for 1 month then the brown egg will stay more dense than the white egg because the hen that lays brown eggs are larger and consume more food than hens that lay white shell eggs and therefore the shell of the brown eggs will protect the inner albumen and yolk more efficiently and will stay more dense than the shell of the white eggs. Also, egg shells are mainly calcium carbonate held together with protein matrix. The brown egg shell contains a tiny bit more protein matrix than the white egg shell. With more protein matrix, the calcium carbonate would be held together more strongly, and therefore would protect the inner albumen and yolk more efficiently and the egg will stay more dense and fresh. A white shell egg and a brown shell egg with the same initial density, mass and volume was left outside the refrigerator for 1 month. The density was calculated every week at the same time by using the formula mass/volume. The egg was weighed on a scale to find the mass and the displacement method was used to find the volume of the egg. The results supported my hypothesis because it showed that the brown egg does stay more dense and fresh than the white egg. The difference in density between the brown egg and the white egg varied for my three trials. My first trial showed that the brown egg stays 0.02 g/ml more dense than the white egg. My second and third trial showed that the brown egg stays 0.01 g/ml more dense than the white egg. In conclusion, the colour of the egg shell does affect the density and freshness of the egg.