Name:________________________________
LAB – OSMOSIS IN POTATOES
**Objectives:
**Hypothesis:
You will observe potato slices in various solutions.
You will determine if the potato has lost or gained H2O.
Tap H2O - _______________________________________________________
**Materials:
Salt H2O - _______________________________________________________
Potato slices
Plastic cups
Salt solution
Tap water
**Procedure:
String Scale
1.
Develop your hypotheses.
2.
Label 2 cups with a marker. Label one salt , label the other one tap . Be sure to include your table number and period on each cup as well.
3.
Use the graduated cylinder to place 100 mL of tap water in the tap water solution cup.
4.
Use the graduated cylinder to place 100 mL of salt water solution in the salt water cup. (I have this at my desk).
5.
Come to the front desk to get 2 potato slices. Weigh each one and record your data in the table below.
6.
Record observations of the potato slices prior to placing them in their solutions. (How do they look, feel, etc?)
7.
Place each potato slice in the cup and put the cups in the designated area.
8.
After 24 hours, remove potato slices from solution. Record observations in the table below.
9.
Reweigh the slices and record your data in the table below.
**Data & Observations:
Container Observations prior to solution bath
Mass prior to solution bath
Observations after solution bath
Mass after solution bath
Tap Water
Salt Water
**Results:
1.
In which kind of solution did the cells lose H2O? _________________________________
2.
How can you tell? __________________________________________________________
3.
In which kind of solution did the cells gain H2O? _________________________________
4.
How can you tell? __________________________________________________________

**Conclusions:
1. Describe what happened to the mass of each potato after soaking.
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2. Describe what happened to the texture of each potato after soaking.
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3.
Explain the changes you observed in terms of osmosis. Your answer must include what type of solutions the potatoes were placed (hypertonic, hypotonic, or isotonic).
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4.
Provide an error analysis in the space below.
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**Challenge: During the winter, salt is often spread on icy roads. The plants along the sides of these
roads often do not survive. Explain the relationship between the plants and the salt on
the roads.
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