Potato Osmosis Lab Report

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;