The Relationship between turgidity of potato cells and the concentration of surrounding medium

Variables:

The variables we are going to work with are the Mass of the potato chip and the Volume of the medium. We will try and keep the mass of the potato chips the same by cutting each chip with a corer and then cut the chips into the same length. Potato chips will be cut out from the same potato in order to obtain a fair test, because different potatoes will be made out of a different structure. We will change the concentration of sucrose in the medium. We will use five different measurements of concentration in order to receive a meaningful result. These measurements of the concentration of sucrose will be distributed into 0%, 25%, 50%, 75% and 100%. Each measurement will be tested three times and the weight of the potato chip will be averaged then compared. Below is a table showing how the concentration of sucrose in the medium is changed.

Concentration of medium %

Volume of H2O

Concentration of Sucrose

0

00

0

25

75

25

50

50

50

75

25

75

00

0

00

Apparatus:

. 1 potato

2. Corer

3. 5 Large beakers

4. Knife

5. Sucrose solution (amount varies within each beaker)

6. Water (amount varies within each beaker)

Method

. Get a potato

2. Use the corer and cut fifteen chips of 2cm potato chips

3. Dry each potato chip with a towel too make sure no additional amount of water is inserted into the solution

4. Set up experiment as shown in diagram below

5. Fill in medium in each beaker with the correct amount of concentration

6. Place 3 potato chips in each beaker, have them secured with a pin (as shown in diagram below)

7. Leave the potato chips in the beakers for 20 minutes

8. Weigh each potato (group) and put in measurements in a table

9. Compare the original weight with the new weight

0. Find differences of original and new weight

Results:

Before

Concentration of sucrose solution (%)

Weight of Potato chip 1

(g)

Weight of Potato chip 2

(g)

Weight of Potato chip 3

(g)

Average Weight (g)

0

.99

2.04

.98

2.00

25

2.12

2.13

2.07

2.11

50

2.04

2.13

2.09

2.09

75

2.04

2.04

2.05

2.04

00

2.13

2.03

2.08

2.08

After

Concentration of sucrose solution (%)

Weight of Potato chip 1

(g)

Weight of Potato chip 2

(g)

Weight of Potato chip 3

(g)

Average Weight (g)

0

2.07

2.11

2.14

2.11

25

2.11

2.18

2.11

2.13

50

2.09

2.02

2.11

2.07

75

.94

.96

.93

.94

00

2.03

.88

.94

.95

Differences between Before and After

Concentration of sucrose solution (%)

Increase (+) / Decrease (-) in Mass

0

+0.11

25

+0.02

50

+0.02

75

-0.10

00

-0.13

Graph of results is shown in a separate sheet of graph paper.

Conclusion:

As we can see from the results and graph, when the concentration of sucrose increases the mass of the potato chip will decrease and vice versa. Therefore the prediction was correct in terms of the results referring to the hypothesis. As osmosis is the flow of a solvent by diffusion through a semi-permeable membrane from a less concentrated solution to a more concentrated one, until the concentrations are equalized.

Evaluation:

The results are reliable because each concentration has been tested 3 times with the same potato and the results have been averaged out. The differences were calculated into 2 decimal places with a calculator. If we were to repeat this experiment and had given more time, I would not put 3 potato chips in the same beaker but would have 3 beakers with the same concentration of the medium in and each with a potato chip. Therefore each potato chip would not have to compete or share the same medium.