Columbia University's Summer Research Program for Secondary Science Teachers
Students investigate osmosis as they determine how carrot cells respond to two different environments
Philip Lalli - Adlai Stevenson HS, Bronx
Aim: How does osmosis affect cells? [Content Standard C- The cell]
Objective: Students investigate osmosis as they determine how carrot cells respond to two different environments
Materials: two 250 mL beakers, distilled water, table salt, carrot sticks, string
1. Fill two 250 mL beakers three-fourths full with distilled water.
2. Add 5 teaspoons of salt to one beaker, stir it, and label it salt water.
3. Obtain two similar carrot sticks. Tie string tightly around each carrot.
4. Submerge one carrot in the salt water beaker and the other carrot stick in the distilled water beaker.
5. Allow the beakers to stand undisturbed for 24 hours.
6. Remove carrot sticks. Observe tightness of threads. Squeeze and bend carrots to determine their texture.
[Content Standard Unifying Concepts- Change, constancy, and measurement]
[Teaching Standard A- Select content and adapt curricula...]
Complete the table
Condition of carrot sticks Type of water
1. Loose thread
2. Cells gained water
3. Soft texture
4. Tight thread
5. Firm texture
6. Cells lost water
1. What was the purpose of tying the thread around each carrot? [Teaching Standard B- Orchestrate scientific discourse]
2. Using your knowledge of osmosis draw a diagram to explain what happened to the cells of the carrots.
3. Why do supermarket workers spray fruits and vegetables with water/
4. Write a detailed conclusion to this lab.
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