Effect of Osmosis on Living Tissue
Ivory Loh Biology 2A
Effects of Osmosis on Living Tissue
Problem
To measure the amount of osmosis potato tissue experience in different
concentrations of sugar solution
Hypothesis
If the sugar solution has a higher or lower sugar concentration than 0.4 M, then
the potato core will shrink or expand in mass, because the isotonic solution for a
potato tissue contains 0.4 M of sugar.
Variables
Independent Variable:
The amount of sugar concentration in the solutions
Dependent Variable
The final mass of the potato cores
Controlled Variables
Time- the same amount of time must be kept in order to ensure an equal amount
of time in which osmosis occurs
Amount of solution- the same amount of solution must be kept because different
amounts of water might change a solution from hypertonic to hypotonic, thus
changing the result
Size of the potato cores- the potato cores have to be the same size because
osmosis might occur differently if the sizes and surface areas are different
Procedure
First, I poured 50 mL of the 6 different sugar concentration solutions (0
M, 0.2 M, 0.4 M, 0.6 M, 0.8 M, 1.0 M) into 6 different plastic cups. After that, I got
12 cylinders of potato cores, and cut all of them into the same length (2.5 cm)
with a razor blade. After that, I dried the 12 cylinders of potato with a paper
towel, and put them into six groups (2 in each group). I took a picture of this and
recorded the flexibility of each core. With an electronic balance, I then found and
recorded the mass of each group of potato cores by measuring them on a
weighing boat and zeroing (subtracting) away the mass of the weighing boat.
After finding the mass of each group of potato cores, I put the 6 groups into the 6
different plastic cups. 24 hours later, I came back and took out each group of
potato cores. After dabbing them dry, I measured and recorded the mass of each
group with an electric balance again. I took a picture of the potato cores after 24
hours and recorded my observations (on color changes, size change, flexibility,
etc.) I then organized my data into a table with the initial mass, final mass,
difference in mass, and percent mass change of the potato core groups. Finally,
when I was done, I threw away the potato cores, cleaned and put away all my
equipments.
Effect of Osmosis on Living Tissue
Ivory Loh Biology 2A
Effect of Osmosis on Living Tissue
Ivory Loh Biology 2A
Data Collection
The Change in Potato Masses in Different Glucose Concentrations
Glucose
concentration
(M)
0.0
0.2
0.4
0.6
0.8
1.0
Initial Mass
(±0.01g)
1.07
1.09
1.08
1.08
1.07
1.10
Final Mass
(±0.01g)
Difference
(±0.01g)
1.24
1.28
1.06
0.83
0.77
0.67
0.17
0.19
-0.02
-0.25
-0.30
-0.43
Percent
Mass
Change (%)
15.89
17.43
-1.85
-23.15
-28.04
-39.10
Formula to find the difference: Final mass - Initial mass eg. 1.24g 1.07g = 0.17g Difference = 0.17g
Formula to find the Percent Mass Change: ((Final mass - Initial
Mass) / Initial mass) x 100 eg. ((1.24 - 1.07) / 1.07) x 100 => (0.17 /
1.07) x 100 => ≈0.1589 x 100 => 15.89%
Observations:
Note: Flexibility Scale= 1 (not flexible) to 5 (very flexible)
Before the experiment, all of the potato cores had about the same flexibility. It
was somewhat flexible, but I couldn’t really bend it all the way.
Flexibility of all the potato cores before the experiment = 2
Note: Group 1 = 0 M of sugar concentration
Group 2 = 0.2 M of sugar concentration
Group 3 = 0.4 M of sugar concentration
Group 4 = 0.6 M of sugar concentration
Group 5 = 0.8 M of sugar concentration
Group 6 = 1.0 M of sugar concentration
Effect of Osmosis on Living Tissue
Ivory Loh Biology 2A
After 24 hours, I noticed other changes, besides from the increase or decrease in
mass, in the different groups of potato cores.
Group 1 – The potato cores became more fragile and it was much easier to break
than before. The color also became paler. When I pressed it, it was also very hard
and less squishy than before.
Flexibility = 1.5
Group 2 – The potato cores in this group was very similar to the potato cores in
the 1st group. It also became very brittle, although it was less hard than the
potato cores in the 1st group. The color became lighter than before, but it was
slightly darker than the potato cores in the 1st group.
Flexibility = 1.5
Group 3 – The potato cores in this group was around the same flexibility as how
it was before it was soaked in the solution for 24 hours. However, it became
slightly more bendable and less easy to break than before. When I pressed it, the
potato cores were somewhat hard.
Flexibility = 2.5
Effect of Osmosis on Living Tissue
Ivory Loh Biology 2A
Group 4 – The potato cores in this group was about the same color as how it was
at the start. However, when I fully bent the potato core, it did not break.
Additionally, the potato core became slightly softer than before.
Flexibility = 3
Group 5 – The potato cores in this group became very flexible. It can be turned
and twisted in almost all directions. Its color also became somewhat darker and
softer than before.
Flexibility = 4
Effect of Osmosis on Living Tissue
Ivory Loh Biology 2A
Group 6 – The potato cores in this group became extremely flexible. It could be
completely twisted and bent in all directions and ways. I easily made an “s”
shape with the potato core, and it stayed like that until I remodeled it. The potato
core became extremely soft and was not brittle at all. Furthermore, the color of
the potato cores got darker and was a lot darker than the pale potato cores from
the first group.
Flexibility = 5
Data Analysis
Change in Potato Mass in Different
Glucose Concentrations
0.3
Change in Mass (g)
0.2
0.1
0
-0.1
0
0.2
0.4
0.6
0.8
-0.2
-0.3
-0.4
-0.5
Glucose Concentration (M)
1
1.2
Effect of Osmosis on Living Tissue
Ivory Loh Biology 2A
Percent Mass Change (%)
Percent Potato Mass Change in
Different Glucose Concentrations
30
20
10
0
-10 0
0.2
0.4
0.6
0.8
1
1.2
-20
-30
-40
-50
Glucose Concentration (M)
Both of these graphs show a negative relationship. In the first graph, it means
that when the glucose concentration increases, that change in mass of the potato
cores decreases. In the second graph, it means that when the glucose
concentration in the solutions increase, the percent mass change also decreases.
In addition, in both of these graphs, the data for Group 2 (0.2 M glucose
concentration) is an outlier. This is because I didn’t shake the bottle before I
poured the 0.2 M glucose concentration solution into the plastic cup like I did
with the other solutions. This caused the data to be slightly different to what it
should have been if it was following the trend line.