Cell Membrane and Homeostasis Experiment
Objective(s): The reason for this experiment is to see how starch and iodine affect each other and how a plastic bag works similar to a membrane in certain situations.
Introduction: I know prior to doing this experiment that iodine mixed with starch creates a dark color and that most objects, organic and inorganic, naturally experience isotonic reactions.
Hypothesis: I think that the potato will absorb more starch than the sweet potato and they will both absorb relatively similar amounts of water.
Procedure: Variables: Controlled- water and size of potatoes. Manipulated variables- potatoes growth based on contents of solution.
Data and Observations
Bag Content Initial color of water/iodine solution in the cup Final color of the solution in the cup
Starch and Water Dark blue, purple Blackish Blue
Water Orangey Orange
1. Restate your hypothesis and discuss if the observed results supported the hypothesis.
- Based off what I observed, my hypothesis, stating that the potato will absorb more starch than the sweet potato, was correct.
2. Identify the control and variables in your experiment.
- Variables: Controlled- water and size of potatoes. Manipulated variables- potatoes growth based on contents of solution.
3. Why do we observe the color of the solution before adding the sandwich bags to each cup?
- To make sure that the solutions contain the necessary contents.
4. Based on your observations, is the sandwich bag permeable to starch? To iodine?
- Iodine is permeable to the sandwich bag, while starch is not.
5. Look up the molecular structures of starch and iodine, and use those structures to explain your observations.
- Starch is a more complex compound than iodine, making it easier for iodine to pass through objects.
6. If a balance was available, describe how you could use it in this experiment and what the purpose would be.
- The balance could be