Instructions: In this lab activity, you will investigate membrane permeability to specific
substances and how that affects diffusion. You will also investigate how the concentration of a
solution will affect the water potential of a plant cell. Lastly, you will create your own
investigation to test the effects of cell size or temperature on the exchange of materials between
cells and the environment. Submit your lab report to your instructor when completed.
Title: Diffusion and Osmosis Lab Report
Objective(s):
● Explain concepts of diffusion and osmosis
● Investigate how the concentration of a solution will affect the water potential of a
plant cell
● Investigate how membrane permeability affects diffusion
● Test for the movement of molecules using indicator chemicals
Hypothesis:
As described above, there are three parts to this investigation, each with different variables.
Review the procedures section. Then write a prediction for each part of your investigation. Be
sure to compare your independent variable to your dependent variable using an "if /then” for
each hypothesis statement.
Lab Safety:
● Wash your hands before and after handling lab materials.
● It is important to always protect your eyes during lab activities. Wear protective goggles
whenever possible.
● When working at the kitchen counter or table, be sure to protect the workspace from
spills and clean up any splashes or spills immediately.
● All materials in this lab activity are safe to dispose in the garbage (solids) and down the
drain (liquids only).
Procedure:
, A list of materials and summary of steps is provided for you in part 1 and 2. However, you are
responsible for the summary of steps in part 3.
Materials:
Four large plastic cups or bowls
Eight small cups/bowls
Two thin non-durable zip-lock plastic sandwich bags (the generic version work best)
Measuring cups and spoons
Iodine
¼ cup cornstarch or small potato
Strainer (optional)
Paper towels
100 mL distilled water
60 g or 5 tbs sugar (sucrose)
One potato
One of the following: sweet potato, pear, or apple
Aluminum foil or plastic wrap
Knife
Metric ruler
Summary of Steps:
Part 1: Cell Permeability
Controlled variables: distilled water
Independent variable: whether a solution has starch