# Effect of Surface Area to Volume Ratio on Rate of Osmosis

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_An experiment on the effect of surface area to volume ratio on the rate of osmosis of Solanum tuberosum L._

BACKGROUND

A cell needs to perform diffusion in order to survive. Substances, including water, ions, and molecules that are required for cellular activities, can enter and leave cells by a passive process such as diffusion. Diffusion is random movement of molecules in a net direction from a region of higher concentration to a region of lower concentration order to reach equilibrium. Diffusion does not require any energy input. Diffusion is needed for basic cell functions - for example, in humans, cells obtain oxygen via diffusion from the alveoli of the lungs into the blood and in plants water
OBSERVATIONS

There were no qualitative changes to the potato that could be detected by the five senses after the cubes were taken out of the water

The water level in the beakers did not have any significant decrease

RESULTS (PROCESSED DATA)

Cube Size (cm)

Surface Area (cm2)

Volume (cm3)

Surface Area : Volume

Mass Before (g)

Mass After (g)

Percentage Change (%)

1 x 1 x 1

6

1

6:1

0.96

1.07

11

1.5 x 1.5 x 1.5

13.5

3.375

4:1

3.47

3.62

4.27

2 x 2 x 2

24

8

3:1

7.76

8.26

7.66

2.5 x 2.5 x 2.5

37.5

15.625

2.4:1

14.22

14.93

5.02

3 x 3 x 3

54

27

2:1

25.74

27.05

5.11

Percentage Change calculation:

Average Percentage Change:

CONCLUSION

In conclusion, the potato cube with the highest surface area to volume ratio (the 1x1x1 cube) had the fastest rate of diffusion as it had the largest percentage increase in mass. While all the other cubes of potato had larger increases in mass at face value compared to the smallest cube, the smallest cube had the largest overall gain in percentage. The results support my hypothesis that the smallest cube will have a higher rate of osmosis because it has a proportionally larger amount of surface area compared to its volume.

As seen from the graph above, despite my hypothesis being correct, the trend in the percentage increase of mass was not a steady