How does the concentration of a solution affect the change in mass of a potato piece soaked in it? In Year 10 Science, students are investigating osmosis, which is the diffusion of water. Water naturally diffuses from areas of high water concentration to areas of low water concentration. Students measure the initial mass of a potato piece, soak it in a solution, and then weigh the final mass of the potato after it has soaked. The change in mass of the potato piece determines whether water diffused into, or out of, the potato. Other factors that affect this investigation include initial moisture of the potato, solution type, temperature of the solution, and surface area of the potato piece.