Osmosis is the diffusion of water across a semipermeable membrane, from an area of high water concentration to an area of low water concentration. Osmosis may occur in response to changing concentrations of water-soluble solutes, such as sugar or salt. Osmosis can be observed in individual cells or in collections of cells, as in multicellular organisms or their structures. In this investigation you will use a shelled (decalcified) egg’s external membrane to demonstrate how osmosis can occur in solutions where there are changes in the concentrations of solutes in the external environment of the egg. Other than the external membrane, eggs have two components, the yolk and the white. The yolk is the food source for a developing chick, thus it contains essential vitamins, minerals, fats, cholesterol, and a few proteins. The white contains mostly water, with a small amount of dissolved proteins.