Purpose: To demonstrate the process of osmosis.
Hypothesis: After reading the procedure state a testable hypothesis.
If (dependent variable) then
(independent variable)
Materials:

Salt (NaCl)
Sugar
Distilled water
Coke/Diet Coke/Monster
4 – Plastic Cups
Marker
Paper Towel
Stir Rod
Balance
Weigh Tray
100 mL Graduated
Cylinder
3 Potato Slices

Procedure:
1. Use a balance to measure the mass of each potato slice and record your data in Data Table 1.
2. Use a wax pencil or marker to label 3 cups: Cup 1, Cup 2, and Cup 3.
3. Use a 100 mL graduated cylinder to measure 200 mL of distilled into each of the 3 cups.
4. CUP 1- Use the balance to measure 30g of salt and stir until completely dissolved.
5. CUP 2- Use the balance to measure 30g of sugar and stir until completely dissolved.
6. CUP 3- Contains 200 mL of distilled water ONLY.
7. Place one potato slice into each cup and allow it to soak for 30 minutes or overnight
8. After 30 minutes, remove each potato slice from its cup and blot dry using a paper towel.
9. Use a balance to measure the mass of each potato after soaking and record your data in Data Table 1. (Be careful to record each sample in the correct location – Do not mix them up).
10. Calculate the difference in mass before and mass after and record in Data Table 1.
11. Use Data Table 1 to construct a BAR GRAPH showing the initial and final mass for each potato slice. Be sure to include: a Title, label each Axis, and a Key for your bars.

Data:
Data Table 1 – Potato Osmosis
Cup #
Beginning Mass
of Potato/Carrot (g)
Ending Mass of
Potato/Carrot (g)
Change in Mass
(g)
% Change in
Mass
1
200mL H2O +
30g of Salt

2
200mL H2O +
30g of Sugar

3
200mL H2O

4
200mL

Analysis:
1. The following formula is used to calculate percentage change:
New Mass – Original Mass x 100%
Original Mass
2. Calculate the percentage change for each of your samples and record your results in Data Table 1.
(SHOW YOUR WORK):
a. Salt Water:

b. Sugar Water:

c. Distilled Water:

3. How do your results compare to the class results?
Conclusion:
1. From your data table, identify which solutions were isotonic, hypotonic, and hypertonic solutions in relation to the potato slice?

2. Does your data support your hypothesis? Use your actual data to support your answer.

3. Identify 2 possible sources of error in your experiment and describe 1 way to correct each of your sources of error: