1. Potato Osmosis (…and some other ideas)

2. 9-12.L.1.1. Students are able to relate cellular functions processes to specialized structures within cells. Concepts: Osmosis Hypertonic/hypotonic/isotonic Problem solving Graphing and analyzing graphs

4. If the cell had a concentration of 0.2M sucrose, what might be the concentration of the surrounding solutions in A, B and C?

5. Challenge Question Can you determine the concentration of sucrose in a potato?

6. Data collected:

8. 0.35 M

9. 0.37 M

12. Students make their own solutions, cut their own potatoes, etc. Allow procedural mistakes Student-directed graphs Solutions are made ahead of time by teacher, divided up by the class, or only dilutions are required. Make sure procedures are correct before allowing experimentation Potatoes cut into equal sized pieces ahead of time Require certain graphs at the end of the experiment Easier:Challenging:

13. Potato nutritional value Is this experiment really measuring the sucrose concentration?

14. MolalityNaClSucroseGlucose 011.02%9.57%11.92% 0.14.88%7.23%6.54% 0.2-4.81%1.66%4.44% 0.3-14.16%-4.13%-0.74% 0.4-20.86%-10.82%-8.29% 0.5-25.16%-15.98%-15.66% http://biology.clemson.edu/bpc/bp/lab/110/osmosis.htm Average percent change in mass of white potato cores during a 1.5-hour incubation in several NaCl, sucrose, and glucose solutions.

16. Other ideas: Grape lab – Middle School Discussion/writing probes

17. Show what you know… Salting the earth refers to the practice of spreading salt on fields to make them incapable of being used for crop-growing. This was done in ancient times at the end of some wars as an extremely harsh tactic designed to hurt an entire population of people. (The lack of crops would lead to food shortages.) Based on your knowledge of cells and cell transport, explain why salting the earth was an effective way to destroy plants.