Name: _______________________
Period: _______________________ Date: _______________
OBSERVING OSMOSIS
It is difficult to see osmosis occurring in cells because of the small size of most cells.
However, there are a few cells that can be seen without the aid of a microscope. Try this
activity to see how osmosis occurs in a large cell.
Pre-laboratory questions: Answer in full and complete sentences.
1. What is diffusion? ______________________________________________________
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2. What is osmosis? _______________________________________________________
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3. What is an example of a cell that is large enough to be seen without a microscope?
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Problem:
How does osmosis occur in an egg cell?
Materials:
 Raw egg (2)
 250mL beakers (4)
 250mL vinegar
 250mL corn syrup
 250mL salt water
 Carrot
 Flower in colored water
Procedure:
1. Make a hypothesis for each of the 4 beakers (egg in corn syrup, egg in vinegar, carrot
in salt water and flower in colored water).
2. Record the original mass of the eggs and the carrot. Record the color of the flower.
3. Place one egg in a beaker with the corn syrup, place one egg in a beaker with the
vinegar, and place the carrot in the beaker with the salt water.
4. Record the pH of the vinegar.
5. Record visual observations of the 4 beakers for days 2-4.
6. After 1 week test the pH of the beaker with the egg in vinegar.
7. Obtain the mass of the eggs and the carrot. Record the color of the flower.
8. Place the egg from the beaker with the vinegar into the beaker with corn syrup. Leave
overnight.
Hypothesis:
Beaker I: Egg in vinegar
Hypothesis: The high concentration of water is in the ___________________________.
(egg or vinegar)
The water will move _________________________________ the egg. This will
(into or out of)
________________________________________ the mass of the egg.
(increase or decrease)
Beginning of experiment (Day 1)
After 1 week (Day 5)
Observations: (Is the egg less or more dense than the vinegar? Is a chemical change
occurring and how can you tell? Is there any change in size and color?)
Day 2:
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Day 3:
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Day 4:
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Beaker II: Egg in corn syrup
Hypothesis: The high concentration of water is in the ___________________________.
(egg or corn syrup)
The water will move _________________________________ the egg. This will
(into or out of)
________________________________________ the mass of the egg.
(increase or decrease)
Beginning of experiment (Day 1)
After 1 week (Day 5)
Observations: (Is the egg more or less dense than the corn syrup? Is there any change in
size and color?)
Day 2:
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Day 3:
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Day 4:
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Beaker III: Carrot in NaCl + H2O
Hypothesis: The high concentration of water is in the ___________________________.
(carrot or salt water)
The water will move _________________________________ the carrot. This will
(into or out of)
________________________________________ the mass of the carrot.
(increase or decrease)
Beginning of experiment
After 1 week
Observations: (Is the carrot more or less dense than the salt water? Is a chemical
change occurring and how can you tell? Is there any change in size and color?)
Day 2:
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Day 3:
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Day 4:
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Beaker IV: White flower in colored H2O
Hypothesis: The high concentration of water is in the ___________________________.
(flower or water)
The water will move _________________________________ the flower. This will
(into or out of)
change the color of the flower to ____________________________________________.
Beginning of experiment
Color water
After 1 week
Color water and flower
Observations: (Be specific as to where the color is on the flower and how much is there.)
Day 2:
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Day 3:
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Day 4:
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Data:
Substance
Egg in Vinegar
Original Mass
Ending Mass
Original pH
Ending pH
Egg in Corn Syrup
Carrot in NaCl + H2O
pH of vinegar
Post Lab Questions: Answer the following questions in full and complete sentences.
1. If water is moving into a cell will the cell get bigger or smaller?
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2. If water is moving out of a cell will the cell get bigger or smaller?
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3. What is the law of conservation of matter?
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4. What type of reaction did the egg shell in the vinegar go through?
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5. Was the egg shell in the vinegar destroyed? Explain your answer.
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