Biology Design Practical Joshua Edwards What are effects of the volume of a potato and the amount of weight it loses when placed in salt solution? Introduction This design practical uses a potato’s surface area to volume ratio to see what affects it has on osmosis in different concentrations. Osmosis is the movement of water molecules through a cell membrane into an area of a higher solute concentration. The movement goes the way of the solvent with more solute because the lower solute concentration is drifting through balancing the ratio of solute per solvent (En.wikipedia.org, 2018). Surface Area to Volume Ratio shows the amount of area the entity has versus the amount of space inside the entity. If the entity was a cell for example, a larger ratio is preferred because when the cell grows and gains a smaller ratio the cell will divide because the volume inside had too much demand for the surface area. Therefore, the hypothesis will be: The larger the surface area to volume ratio the potato has, the weight will have more of a dramatic change. Variables Independent Surface Area to Volume Ratio Dependent The percentage weight change is dependent on surface area of potato Controlled The amount of salt solution used Percentage of salt in solution Length of time the potato is sat in water Materials needed 3 Potatoes 600 ml 15% salt solution Utensils 4x 300 ml beaker Knife Cutting board Scale Ruler Procedure 1. 8 rectangular prisms will be cut from the potatoes;