Diffusion and Osmosis Lab
Starch and Iodine
Initial set up:
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MF-MI
X 100
Obtain a piece of dialysis tubing or plastic baggie.
MI
Make sure one end is closed or tied off.
Add about 10-15 mL of starch solution. (two-three finger widths)
How to calculate % change
Tie off the other end and make sure it does not leak.
Record the initial color of the baggie below.
Fill a beaker ¾ full of water and add 5-8 drops of iodine.
Record the initial color of the beaker below.
Place the tubing in the iodine solution.
Wait 5 minutes, take the tubing or baggie out and record the color changes for the baggie and beaker.
Analysis Questions:
1. What are the similarities and differences between glucose and starch?
__________________________________________________________________________________________________
__________________________________________________________________________________________________
2. What is the initial color of the set up?
Beaker Solution _____________
Dialysis Tubing ______________
3. What is the final color of the set up?
Beaker Solution _____________
Dialysis Tubing ______________
Show where
Glucose, Starch and
Iodine are in the
Final State.
4. What moved into the baggie? ______________________
5. What moved out of the baggie? _____________________
6. What determined what was able to move across the baggie (membrane)?
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Potato Cell Osmosis
Initial set up:
1. Cut 3 samples of potatoes, as close to equal in mass and surface area.
2. Record their initial mass.
3. Place each sample in a different solution concentration (0 M, 0.4 M, 1.0 M) for 20 minutes.
4. Remove each sample and record the final mass.
Potato Sample 1
Potato Sample 2
Potato Sample 3
Initial Mass (g)
Final Mass (g)
Difference (g)
% Difference
Analysis Questions:
1. Was solution 1 hypertonic, hypotonic, or isotonic?_________________________
2. Was solution 2 hypertonic, hypotonic, or isotonic?_________________________
3. Was solution 3 hypertonic, hypotonic, or isotonic?_________________________
Solution 0M
sugar
P
Solution 0.4M
sugar
P
Draw arrows
showing where
the water moved.
Draw arrows
showing where
the water moved.
Solution 1M
sugar
P
Draw arrows
showing where
the water moved.
Elodea
Initial set up:
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Pick one leaf of elodea, place it on a slide.
Make sure that there is a little water with your leaf. Add a cover slip.
Look at the plant cells under the microscope.
Draw what you see in the diagram below before you add salt water.
Remove the cover slip.
Add 3-5 drops of saline solution to the leaf.
Draw what you see in the diagram below after you add salt water.
Before Salt water
After Salt water – what happened to
the cell membrane?_______________
________________________________
____________________
Egg Osmosis
Initial set up:
1. Weigh egg sample 1 and record the data in the table below.
2. Place an egg sample 1 in the first beaker and cover it with water for 24-48 hours.
3. Weigh egg sample 2 and record the data in the table below.
4. Place the egg sample 2 in the second beaker and cover it with corn syrup for 24-48 hours.
5. Record the mass of both eggs after the 24-48 hours window.
Egg Sample 1
Egg Sample 2
Initial Mass (g)
Final Mass (g)
Difference (g)
% Difference
Analysis Questions
1. What happened to the egg placed in the water solution? _________________________________________
2. What happened to the egg in the sugar solution?________________________________________________
Original size of
the egg
Solution water
Draw arrows
showing where
the water moved.
Solution corn syrup
Draw arrows
showing where
the water moved.