Factors Affecting the Rate of Osmosis samples decreased during OD process are temperature, surface area, difference in water potential and concentration gradient. Which, the higher the temperature, the faster the movement of water molecules across the semi permeable membrane, The larger the surface area, the more space for the molecules to move easily across; the smaller the area, the more restricted the movements of the molecules and the slower the movement, The higher the difference in water potential, the faster the osmosis; for the lesser water molecules are in the region of low concentration, more water molecules from the region of higher concentration can enter faster and easier and the movement of osmosis is affected by the concentration gradient; the lower the concentration of the solute within a solvent, the faster osmosis will occur in that solvent.