Student Name
Date
How Does the Conentration of a Solution
Affect Osmosis? (Potato Lab)
Question
How does the concentration of salt affect osmosis?
Hypothesis
If salt water draws water out of cells, then the potato in the saltier water should lose more mass.
Materials
See page 33, then list the materials you will be using.
Procedures
Outline your plan, make a data table.
Analysis
Make a graph using the data in your table
Conclusion
Was your hypothesis supported, or rejected? Explain
Question:
How does the concentration of salts affect potatoes?
Hypothesis:
If salt water draws water out of cells, then the potato in the
saltier water should lose more mass.
Materials:
After making a plan, list the materials you will need:
_____________________________________
_____________________________________
_____________________________________
Procedures:
You will be given two potato cubes, and two salt solutions:
one that is 5% and one that is 10% salt. Plan how you will
measure which potato loses more water over time. Check
this plan with your teacher, then list the materials needed
above, and list the procedures below.
Procedures:
To make sure you have a valid experiment planned, answer
the following questions:
1. What variables will you attempt to control during the
experiment?
Size and shape of potato, temperature of solutions
2. What is the independent variable, ie. The thing you
purposely change?
The concentration of salt water, eg. 5% vs. 10% salt water.
3. What is the dependent variable, ie. the thing that you
expect to change because of the independent variable.
The mass of the potato cubes, after being in salt water
solutions.
Procedures cont’d:
Copy the data table:
Time (min)
0
2
4
6
8
10
Mass in 5% Mass in 10%
Solution (g) Sol’n (g)
Analysis:
Make a graph as in (e) p. 33. Put mass on the
side, or y-axis, and time on the bottom, or x-axis.
Spread your numbers evenly along the length/height of the
page. Include the units.
Give your graph a descriptive title.
Changing Mass of Potato in Different
Concentrations of Salt Water
3.00
2.50
2.00
5% Sol'n
10% Sol'n
Mass (g)
1.50
1.00
0.50
0.00
0
2
4
Time (min)
8
10
Conclusion:
Was your Hypothesis supported, or rejected?
Why should the potato in the 10% solution be
lighter than the one in the 5% solution?
My hypothesis was supported. The potato in the 10%
solution should have been lighter because the cytoplasm
has a higher concentration of water than the salt solution,
so water osmossed out of the cell.