Demonstrating Osmosis

Demonstrating osmosis
Introduction
The movement of water in and out of a system bounded by a membrane permeable to water, but not certain other substances, can be inferred by either mass changes or volume changes in that system. It is possible to monitor other changes in physical conditions, such as texture. Monitoring mass enables quantification of the changes, whereas other changes may only be qualitatively measured.
Equipment / materials

4 eggs
Sugar
Distilled water
Acetic acid
Scales
Tissue
Gloves
4 beakers

Procedure
• Eggs have been previously prepared by soaking them in 4% acetic acid for about 3 days. The acid will dissolve the shell, and leave the membrane and contents intact.
• Remove four eggs from the acid and blot them to remove excess fluid from the surface.
• Measure the mass of each egg
• Place two eggs in distilled water
• Place the other two eggs in a strong sugar solution
• Monitor the weight change over the next few hours.
• Note any changes in texture
Data
Raw data
Egg A
Egg B
Egg C
Egg D
82.76g
84.78g
83.75g
98.42g

Trend table
Time / Egg
Egg A
Egg B
Egg C
Egg D
11:20
82.76g
84.78g
83.75g
98.42g
11:50
79.66g
80.48g
86.66g
102.46g
12:20
77.18g
77.20g
87.90g
105.32g
12:50
76.09g
75.78g
88.11g
106.52g
1:20
75.14g
74.83g
88.10g
106.85g
1:50
74.72g
74.43g
87.76g
106.56g
*The egg D had been broke when we were weighing it so this result may not be really correct.
Trend graph

Percentage graph

Average / Egg
Egg A
Egg B
Egg C
Egg D
Change in average
82.76g - 74.72g
Decrease 1.808g
84.78g - 74.73g Decrease 2.06g
83.75g – 87.76g
Increase 0.784g
98.42g – 106.56g
Increase 1.628g
Change in average of eggs from 11:20 – 1:50 (30 minuteseach)

Change of Egg A
Time / Egg
Egg A
11:20 ~ 11:50
4.1g
11:50 ~ 12:20
2.48g
12:20 ~ 12:50
1.09g
12:50 ~ 1:20
0.95g
1:20 ~ 1:50
0.42g

Change of Egg B
Time / Egg
Egg B
11:20 ~ 11:50
4.3g
11:50 ~ 12:20
3.23g