Group 4: Jordan Wahl, Amanda Olson, and Alyssa Sorce.
Osmosis Lab Report
What is Osmosis?
Osmosis involves the process of concentrations of water getting separated by a permeable membrane.
It also is a specific process of diffusion, solute cells spreading throughout the solvent, involving water
as the solvent.
If we place a hypertonic solution in a hypotonic solution, then the hypotonic solution will move
towards the hypertonic solution.
Materials:
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4 15-cm lengths of dialysis tubing, soaking in dH²O
8 10-cm pieces of string
Ring stand and funnel apparatus
25-mL graduated cylinder
4 small string tags
4 400 mL beakers
Paper toweling
Balance
Source of dH²O (at each sink)
Sucrose solutions 15% and 30%
Scissors
Procedure:
1. Obtain four sections of dialysis tubing, each 15 cm long, that have been presoaked in distilled
water. Recall that the dialysis tubing is permeable to water molecules but not to sucrose.
2. Fold over one end of each tube and tie it tightly with a sting.
Group 4: Jordan Wahl, Amanda Olson, and Alyssa Sorce.
3. Slip the open end of the bag over the stem of a funnel and using a gradulated cylinder to
measure volume, fill the bags as follows:
Bag 1: 10 mL of distilled water
Bag 2: 10 mL of 15% sucrose
Bag 3: 10 mL of 30% sucrose
Bag 4: 10 mL of distilled water
4. As each bag is filled, force out excess air by squeezing the bottom end of the tube.
5. Fold the end of the bag and tie it securely with another piece of string.
6. Rinse each filled bag in the dishpan containing distilled water (dH²O); gently blot off the excess
water with paper toweling.
7. Weigh each bag to the nearest 0.5 g.
8. Record the weights in the column marked “O min” in the table.
9. Number four 400 mL beakers 1 to 4.
10. Add 200 mL of dH²O to beakers 1 through 3.
11. Add 200 mL of 30% sucrose solution to beaker 4.
12. Place bags 1 through 3 in the correspondingly numbered beakers.
13. Place bag 4 in the beaker containing 30% sucrose.
14. After 20 minutes, remove each bag from its beaker, blot off the excess fluid, and weigh each
bag.
15. Record the weight of each bag in the table.
16. Return the bags to their respective beakers immediately after weighing.
17. Repeat steps 14 through 16 at 40, 60, and 80 minutes.
18. At the end of the experiment, take the bags to the sink, cut them open, pour the contents down
the drain and discard the bags in the garbage. Pour the contents of the beakers down the drain
and wash them.
Group 4: Jordan Wahl, Amanda Olson, and Alyssa Sorce.
Results:
Bag 1 (distilled water/distilled water)
0 min- 10.5g
10 min- 11.0 g
50 min- 9.5 g
Bag 2 (15% sucrose/ distilled water)
0 min- 10.0 g
10 min- 10.5 g
50 min- 9.5 g
Bag 3 (30% sucrose/ distilled water)
0 min- 10.0 g
10 min- 10.5 g
50 min- 9 g
Bag 4 (distilled water/ 30% sucrose)
0 min- 9.5 g
10 min- 9 g
50 min- 5 g
Analysis:
Question 1: Observation?
The bags that were placed in distilled water (Bags 1 through 3) generally maintained weight within
range. The bag placed in the 30% sucrose rapidly decreased its weight. Bags 2 and 3 were supposed
to gain weight and bag 1 was supposed to maintain weight.
Question 2: Was the direction of net movement of water in bags 2 to 4 into or out of the bags?
Bag 2 gained weight as the hypotonic solution outside of the bag moved towards the hypertonic
solution inside the dialysis tubing. Bag 4 lost weight as the hypotonic solution within the bag moved
out into the beaker that was filled with the hypertonic solution.
Question 3: Bag 3 gained the most weight because the hypotonic solution in the beaker moved towards
the 30% sucrose solution within the dialysis tubing.
Conclusions:
Within this lab demonstrating Osmosis, the hypotonic solutions moved towards the hypertonic
solutions whether inside the tubing or outside.
Sources of errors could’ve been a result from time issues, tying strings improperly, or the amounts in
the bags.
Group 4: Jordan Wahl, Amanda Olson, and Alyssa Sorce.