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Carrot Lab
Name:
Block:
This Lab will show you the following:
 Water flows relatively easily across a membrane.
 The flow of water across a membrane is called OSMOSIS. Water will flow from its higher concentration to
its lowest concentration. Osmosis is really just the “diffusion of water molecules”.
 Solutes that are dissolved in solutions inside potato cells and around the outside of the carrot cells will
affect the movement of water either into or out of the cell.
Testable Question: How will the concentration of solutes in different solutions affect the movement of water?
*The movement of water will be measured by using the change in the mass of a carrot.
Materials:
3 carrots
marking pen
graduated cylinder
distilled water
balance
paper towel
3 small jars
0% sugar solution
25% sugar solution
50% sugar solution
Procedure:
1) Create a table that would organize the following: Concentration of Outside Solution, Initial Mass
of Carrot, Final Mass of Carrot, Change in Mass, & % Change in Mass.
2) Obtain 3 jars. Use tape or another marking device to label each container with one of
the following: 0% sugar, 25% sugar, 50% sugar
3) Obtain 3 carrots, zero your scales and find the initial mass of each. Record the information in the
appropriate place on your table & place the carrot in the right jar.
4) Immediately fill each jar with just enough solution to cover the carrots
5) Place a lid or plastic wrap on top of the containers. See the teacher for rubber bands if using plastic
wrap. Put the jars in the location discussed earlier in class.
After 48 Hours:
6) After 48 hours, remove the carrots from the solution (remembering which solution each was in). Blot
the carrots dry, being careful not to squeeze them too much.
7) Zero the scales and find the final mass of each carrot. Record and calculate your results to
complete your tables. *Remember to dry / wipe off scale if needed!
8) Calculate the change in the carrots mass by final mass – initial mass.
9) Calculate the % change in mass by the following formula: final mass – initial mass x 100
initial mass
10) Complete the rest of your write-up.
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Potato Lab
Pre-lab Questions:
Name:
Block:
1) In the 50% sugar solution, water / sugar would be considered the solute. (Circle one.)
2) The solution inside of a carrot would be considered hypertonic / hypotonic / isotonic compared to distilled
water (100% water).
3) Compare the two solutions below. Fill in the blank to indicate which beaker is Hypertonic & which beaker is
Hypotonic.
4) The two diagrams below show carrots in two different solutions. For each diagram draw an arrow in the
direction that osmosis will occur. (The arrows will either point into or out of the carrot.)
Carrot 1
Carrot 2
5) Which Carrot sample (1 or 2) in the example above would experience the greatest turgidity?
____________
6) Which Carrot sample (1 or 2) would have cells similar to cells in a plant that has wilted? ___________
7) If the concentration of solute molecules outside a cell is lower than the concentration in the cytoplasm, is the
external solution hypotonic, hypertonic, or isotonic compared to the cytoplasm? *Draw a picture if you need
help deciding.
8) Using what you know about osmosis, explain what would happen to a jellyfish (an ocean organism) placed
in a freshwater lake. Make sure you discuss what will happen to the cells of the jellyfish.
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Lab Write-up
Name:
Block:
1. What is the question or problem that might be the basis for this investigation?
2. Identify the independent and dependent variable in the experiment.
Independent Variable: _________________________________________________
Dependent Variable: ___________________________________________________
3. Identify two factors that should be held constant for this investigation.
a)
b)
4. What is the control group for this investigation?
5. Write a testable hypothesis for this experiment.
6. Table: *Create a table according to Step 1 in the Procedure.
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7. Graph: *Create a graph that would clearly display the change that took place between the initial mass and
the final mass of the carrot.
8. Do you accept or reject your hypothesis statement? ________________________________
9. Explain in at least 3 sentences what the changes were AND why the changes occurred in each solution.
You should discuss what you know about hypertonic, hypotonic, and isotonic solutions.
10. Identify 2 possible sources of error for this investigation.
a. ______________________________________
__
b. _____________________________________
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11. Biology students wanted to see if changing the temperature of carrots soaked in a sugar solution would
affect the movement of water in or out of the carrot. Describe at least three essential steps in the procedure
needed to conduct this valid experiment. The procedure must be written so that students in another science
class could clearly follow your instructions and successfully complete the investigation.
1. _____________________________________________________________
_____________________________________________________________
_____________________________________________________________
2. _____________________________________________________________
_____________________________________________________________
_____________________________________________________________
3. _____________________________________________________________
_____________________________________________________________
______________________________________________________________
12) Figure 1 shows a vacuole in a plant cell if the cell was in an isotonic solution.
a) In Figures 2 & 3, DRAW the size of the vacuole if the plant cell had been soaking in the solutions
indicated below.
b) Which cell Figure 1, Figure 2, or Figure 3 would have the lowest turgor pressure?
13) Figure 2 should now diagram what we saw in a past lab when we placed SALT WATER on the plant cells
of an Elodea plant. Describe what has happened to the turgor pressure inside the Plant Cell as a result of the
hypertonic solution?
14) You planned on including grapes on a fruit tray at a party you are hosting. However, the grapes were
bought a little early and you noticed they are now wrinkly instead of plump. What could you do to solve this
problem and still serve the same grapes?
a) Wrinkly grapes have lower / higher (circle one) turgor pressure than plump grapes.
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15) The 2 sides of the container are separated by a membrane that allows BOTH sodium and water
molecules to pass through. Figure 1 shows a distribution of molecules. In Figure 2, draw how the molecules
will be distributed if the container is allowed to sit for an extended period of time. (**Remember – molecules
move until they reach equilibrium.)
Figure 1
Figure 2
Key:
= Sodium Molecules
= Water Molecules
Solution 1
Solution 2
16) The 2 sides of the container are NOW separated by a membrane that allows ONLY water molecules to
pass through. Figure 1 shows a distribution of molecules. Draw an arrow (either or  ) to show the
direction that water molecules will flow.
Side A
Side B
Key:
= Sodium Molecules
Solution 1
Solution 2
= Water Molecules
17) Which solution is considered hypertonic? (Side A or Side B)
Explain:
18) Using the symbols for sodium and water shown. Draw on the figure below, two solutions (one on each
side) that would be considered isotonic solutions.
Key:
= Sodium Molecules
= Water Molecules
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