Common Biology Lab
Name____________________________
Osmosis
SLE A1: Lab Report
GSE: LS1-1 All living organisms have identifiable structures and characteristics
that allow for survival
Purpose: To design and perform an experiment that will explore the relationship
between the concentration of the solution in a cell (or model cell) and the rate
of water movement across the cell membrane.
Question: How will the rate of osmosis differ if five (model) cells filled with
different concentrations of sucrose are placed in distilled water?
Osmosis using different concentrations of sucrose solution
Materials List (use some or all…check the ones you use for your formal lab writeup!!!)

Dialysis tubing (20-25cm long, soaked in water overnight)
 String
 Clear plastic drinking cups or beakers
 Sharpie marker or China marker
 Funnel
 Distilled water
 1.0 Molar sucrose solution (342g sucrose, 1L water) diluted into 250 mL
beakers of 1.0 M, 0.8 M, 0.6 M, 0.4 M, 0.2 M sucrose solutions
 Digital balance
*Anticipated time to see results = 15-30 minutes (all need to be pulled out at the
same time!!!!)  Why?
______________________________________________________________________________
__________________________________________________________________
TO DO:
1. With your group, create a procedure that will provide answers to the question
above.
2. What do you anticipate observing (what is your hypothesis)? What types of
measurements will you take?
3. Create a data table to record your measurements.
4. Create a graph of your data.
Common Biology Lab
Name____________________________
Osmosis
SLE A1: Lab Report
GSE: LS1-1 All living organisms have identifiable structures and characteristics
that allow for survival
SUBMIT
Introduction: Paragraph format required!
Paragraph # 1:
 What is the purpose of the lab?
 What is the question you are answering?
Paragraph # 2:
 Provide Background Information on:
o Osmosis in general (including describing the flow of water during
osmosis  the concentration gradient)
o Osmotic Pressure (including background on Hypertonic,
Hypotonic & Isotonic Solutions)
o Dynamic Equilibrium in osmosis
Paragraph # 3:
What is the hypothesis?
Be sure your background information supports your prediction
(hypothesis).
Your prediction should be specific. If you predict a change will
occur, you must specify the type of change you expect to find.
The following is NOT an acceptable hypothesis:” if five (model) cells are
filled with different concentrations of sucrose and placed in distilled
water then the rate of osmosis will differ.”
Materials:
 Bullet the materials list
Procedures:
1. Number the steps in the procedure. Each step must be a complete
sentence.
2. Don’t forget to add in the hazards/safety measures taken!
Data/Observations/Graph:
 All tables must have a title (example - Table 1: Sugar/Starch Solution
Data), labeled units, and must make sense!
 The graph must have a title (example - Figure 1: Sugar/Starch Solution
Data), labeled units, a key, and must make sense!
 For calculations  (example: calculating change in mass) give one
example using your data for each different type of calculation done.
Common Biology Lab
Name____________________________
Osmosis
SLE A1: Lab Report
GSE: LS1-1 All living organisms have identifiable structures and characteristics
that allow for survival
CONCLUSIONS: Answer the following questions in paragraph form. Do NOT
number these in your conclusion
Paragraph # 1:
1. Restate the purpose and hypothesis
2. Was your hypothesis correct? Use your data to support your assertion.
Example: “the hypothesis was correct because there was a change of
10mg…”
Paragraph # 2:
1. Explain why the rate of osmosis differed in the five model cells filled with
different sucrose concentrations. (Remember: Greater change in mass =
faster rate of osmosis). Use your data (#’s and graph) to support your
conclusions.
2. Why was it necessary to calculate the percent change in mass rather than
simply using the actual change in mass?
3. Could any of the model cells in the experiment that were placed in
distilled water ever reach equilibrium? Why or why not?
4. If the model cells were placed in a liter of .2M sucrose solution which cell
would take the longest to reach equilibrium and why? Which model cell
would take the least amount of time to reach equilibrium and why?
5. How do your results relate to dynamic equilibrium?
Paragraph # 3:
1. When wilted plants are watered, they tend to become rigid. Explain how
this might happen.
2. How is the dialysis tubing similar to an animal cell? Different from an
animal cell?
3. How is the dialysis tubing similar to a plant cell? Different from a plant
cell?
4. What may happen to an animal cell if water moves into it? How does this
differ from what would happen in a plant cell? Explain why there is a
difference between the two.
Paragraph # 4:
1. What could be some sources of error in your experiment? (DO NOT say the
digital scale may have been broken, or the molarity of the sugar in the
beakers was incorrect—that’s simply silly.)
2. What can you do to improve the experiment if you were to do it again?
3. What extra/new questions were generated that would lead to a deeper
understanding of the topic?
Common Biology Lab
Name____________________________
Osmosis
SLE A1: Lab Report
GSE: LS1-1 All living organisms have identifiable structures and characteristics
that allow for survival
Formal lab report check off list.
Check off when
complete
Section
Data table – labeled and units
Calculations
Graph – all graphing rules followed
Conclusions – Paragraph 1
Conclusions – Paragraph 2
Conclusions – Paragraph 3
Conclusions – Paragraph 4
Signed: _________________________________________________________
Submit this sheet with lab.