OSMOSIS LAB
Or
Fresh Water vs. Sea Water
PROCEDURE
Write down Procedure (Notebook pg. 32)
1. Make Table #1 (Notebook pg. 32)
2. Fill out table #1 with class
3. Make table #2 (Notebook pg. 33)
PROCEDURE
4.
Make Hypothesis for each cup (What will
happen to the length of the potato?)
5.
Measure potato slices carefully (Put in table #2)
6.
Make sea water solutions (LABEL)
7.
Drop potato slices into sea water solutions and
cover with plastic wrap
PROCEDURE
MAKE SURE TO GET THE
CORRECT POTATO INTO
THE CORRECT SOLUTION
FRESH WATER VS . SEA
WATER
A shipwrecked sailor
is stranded on a small
desert island with no
fresh water to drink.
FRESH WATER VS . SEA
WATER
She knows she could last
without food for up to a month,
but if she didn’t have water to
drink she would be dead within
a week.
FRESH WATER VS . SEA
WATER
Hoping to
postpone the
inevitable, her
thirst drove her
to drink the salty
seawater.
FRESH WATER VS . SEA
WATER
She was dead in two days.
FRESH WATER VS . SEA
WATER
Why do you think
drinking seawater
killed the sailor faster
than not drinking any
water at all?
FRESH WATER VS . SEA
WATER
Today we explore the cause of the
sailor’s death. We’ll prepare
solutions of salt water to represent
the sea, and we’ll cut up slices of
potato to represent the sailor.
FRESH WATER VS . SEA
WATER
Potatoes are made of cells, as is the sailor!
OBJECTIVE
To determine the cause of the sailor’s death, we will determine the
effects of salt water on slices of potato. Our assumption is that
potato cells will behave like the sailor’s cells in her body. We will
compare salt water to fresh water so we can see if there is any effect
caused by the salt in the water. The fresh water acts as a control in
this experiment.
TABLE 1
Percent Sea Water
10% Sea Water
5% Sea Water
1% Sea Water
Fresh Water
Vol. of 100% Salt
Water (ml)
Vol. of Fresh Water
(ml)
Total Vol. (ml)
TABLE 1
Percent Sea Water
10% Sea Water
5% Sea Water
1% Sea Water
Fresh Water
Vol. of 100% Salt
Water (ml)
Vol. of Fresh Water
Total Vol. (ml)
(ml)
100 ml
100 ml
100 ml
100 ml
TABLE 1
Percent Sea Water
Vol. of 100% Salt
Water (ml)
10% Sea Water
Total Vol. (ml)
100 ml
5% Sea Water
100 ml
1% Sea Water
Fresh Water
Vol. of Fresh Water
(ml)
100 ml
0 ml
100 ml
TABLE 1
Percent Sea Water
Vol. of 100% Salt
Water (ml)
Vol. of Fresh Water
(ml)
10% Sea Water
100 ml
5% Sea Water
100 ml
1% Sea Water
Fresh Water
Total Vol. (ml)
100 ml
0 ml
100 ml
100 ml
TABLE 1
Percent Sea Water
10% Sea Water
Vol. of 100% Salt
Water (ml)
Vol. of Fresh Water
Total Vol. (ml)
(ml)
10 ml
100 ml
5% Sea Water
100 ml
1% Sea Water
Fresh Water
100 ml
0 ml
100 ml
100 ml
TABLE 1
Percent Sea Water
10% Sea Water
Vol. of 100% Salt
Water (ml)
10 ml
Vol. of Fresh Water
(ml)
90 ml
5% Sea Water
100 ml
100 ml
1% Sea Water
Fresh Water
Total Vol. (ml)
100 ml
0 ml
100 ml
100 ml
TABLE 1
Percent Sea Water
10% Sea Water
5% Sea Water
Vol. of 100% Salt
Water (ml)
10 ml
Vol. of Fresh Water
(ml)
90 ml
5 ml
100 ml
100 ml
1% Sea Water
Fresh Water
Total Vol. (ml)
100 ml
0 ml
100 ml
100 ml
TABLE 1
Percent Sea Water
10% Sea Water
5% Sea Water
Vol. of 100% Salt
Water (ml)
Vol. of Fresh Water
(ml)
10 ml
90 ml
100 ml
5 ml
95 ml
100 ml
1% Sea Water
Fresh Water
Total Vol. (ml)
100 ml
0 ml
100 ml
100 ml
TABLE 1
Percent Sea Water
10% Sea Water
5% Sea Water
1% Sea Water
Fresh Water
Vol. of 100% Salt
Water (ml)
Vol. of Fresh Water
(ml)
Total Vol. (ml)
10 ml
90 ml
100 ml
5 ml
95 ml
100 ml
1 ml
0 ml
100 ml
100 ml
100 ml
TABLE 1
Percent Sea Water
10% Sea Water
5% Sea Water
1% Sea Water
Fresh Water
Vol. of 100% Salt
Water (ml)
Vol. of Fresh Water
(ml)
Total Vol. (ml)
10 ml
90 ml
100 ml
5 ml
95 ml
100 ml
1 ml
99 ml
100 ml
0 ml
100 ml
100 ml
TABLE 2
Sample
Initial
Length
(Day 1)
Final
Length
(Day 2)
Change in
Length
Tonicity
Hypo-
10% Salt
cm.
5% Salt
cm.
1% Salt
cm.
Fresh
Water
cm.
Iso-
Hyper-
HYPOTHESIS
1. I think that the 10% salt water solution will cause the potato slice to…
2. I think that the 5% salt water solution will cause the potato slice to…
3. I think that the 1% salt water solution will cause the potato slice to…
4. I think that the fresh water solution will cause the potato slice to…
OSMOSIS LAB DAY 2
(Put this information on pg. 35 in your notebook)
1. Collect cups
2. Remove potato slices carefully
3. Measure slices accurately
4. Fill in Data Table #2
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
cm.
cm.
cm.
cm.
Iso-
Hyper-
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm.
cm.
cm.
cm.
Iso-
Hyper-
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm. 3.9 cm.
cm.
cm.
cm.
Iso-
Hyper-
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm. 3.9 cm
cm.
cm.
cm.
- .3 cm
Iso-
Hyper-
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm. 3.9 cm
cm.
cm.
cm.
- .3 cm
Iso-
HyperX
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm. 3.9 cm
3.8 cm.
cm.
cm.
- .3 cm
Iso-
HyperX
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm. 3.9 cm
3.8 cm. 4.0 cm
cm.
cm.
- .3 cm
Iso-
HyperX
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm. 3.9 cm
3.8 cm. 4.0 cm
cm.
cm.
- .3 cm
+ .2 cm
Iso-
HyperX
DATA TABLE 2
Sample
Initial
Length
(Day 1)
Final Change
Length
in
(Day 2) Length
Tonicity
Hypo-
10% Salt
5% Salt
1% Salt
Fresh
Water
4.2 cm. 3.9 cm
3.8 cm. 4.0 cm
cm.
cm.
- .3 cm
+ .2 cm
X
Iso-
HyperX
OSMOSIS LAB DAY 2
5. Throw potato slices and plastic wrap in garbage
6. Dump out cups and stack on lab table
7. Answer questions on last page of lab handout (notebook pg.
34)
8. Make Bar Graph of results from Data Table #2 for Day 1
and Day 2 potato lengths – put in notebook pg. 34 or 35
BAR GRAPH
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
4.2
3.9
3.8
4
4
3.9
4
4
Initial
Final
10% Salt
5% Salt
1% Salt
Fresh
FORMAL LAB REPORT
• Rough draft – Written in notebook
• Final draft – Written in the following format
FINAL DRAFT
PROBLEM:
1. The problem we are trying to solve is…
2. This problem is important because…
3. The information that is important to know before we begin is…
4. The control in this experiment is…
A. This is the control in the experiment because…
FINAL DRAFT
PROBLEM:
5. My hypothesis was…
A. I made the hypothesis that the 10% salt solution water would cause
the potato slice to…
B. I made the hypothesis that the 5% salt solution water would cause
the potato slice to…
C. I made the hypothesis that the 1% salt solution water would cause
the potato slice to…
D. I made the hypothesis that the fresh water would cause the potato
slice to…
PROCEDURE
1. Materials List – List all materials used in the experiment.
2. List in order how the experiment was performed.
A.
B.
C.
D.
The first thing I had to do was ____________
The next thing I had to do was ____________
After that I ________________
Finally I _______________
RESULTS
1. What quantitative and qualitative observations were you able to make?
(list)
• Quantitative observations are number type observations.
• Qualitative observations are opinions or color observations.
2. Data table (taken from your notebook)
3. Graph
OBSERVATIONS AND
CONCLUSIONS
1. When the potato slices sat in the water overnight they _______________
A.
I think the potato slices did this because ____________
2. Is diffusion, osmosis, or active transport responsible for the changes in
the slices?
A.
Define:
a. Diffusion
b. Osmosis
c. Active transport
OBSERVATIONS AND
CONCLUSIONS
3. The ______ solution is isotonic to potato cells.
A. I know that the solution _______ is isotonic to the potato cells
because _____________
4. Define:
A. Hypertonic
B. Hypotonic
C. Isotonic
OBSERVATIONS AND
CONCLUSIONS
5. The sailor died more quickly drinking salt water than not drinking any
water at all because _______________.
6. I think the sailor died from ____________
7. My hypothesis was correct. OR My hypothesis was not correct.
A. My hypothesis was correct because __________.
OR
My hypothesis was not correct because ____________.