CHAPTER 10 TRANSPORT (TSA / V )

Aim/ Objective:To study the relationship between total surface area per volume ratio and the rate of diffusion.

Problem:What is the relationship between total surface area per volume ratio and the rate of diffusion?

Hypothesis:The larger the total surface area per volume ratio / the smaller the size of cube, the faster the rate of diffusion.

Variables

Manipulated:Total surface area per volume ratio / the size of cubes.

Responding:Rate of diffusion.

Fixed:Volume of Sodium Hydroxide solution/ time taken.

Material:Potato, Colored water,

Apparatus:Penknife, white tiles, beaker, forceps, basin and transparent ruler.

Technique:Calculate the rate of diffusion by using a formula.

Rate of diffusion = Percentage of colored area (%min-1)

Time taken

Procedure: Potato tissues are cut into 1 cm3, 8 cm3, 27 cm3 and 64 cm3 cubes.

Then the cubes are immersed into a basin containing 100ml of colored water.

All the cubes are left for 20 minutes.

After 20 minutes, the outer surface of the cubes are dried with filter paper and cut into two halves.

The percentage of colored area in each cube is estimated by using a girded transparency.

The rate of diffusion of each cube is calculated.

The results are recorded in the table.

Result:Size of cubes / cm3

Percentage of colored area / %

Rate of diffusion / %min-11

8

27

64

Rate of diffusion = Percentage of colored area (%min-1)

Time taken

Discussion The smallest cube has the largest percentage colored area whereas the largest cube has the smallest percentage colored area.

The rate of diffusion is the highest in the smallest cube and the lowest in the largest cube.

The larger the total surface area per volume ratio / the smaller the size of cube, the higher the rate of diffusion.

Conclusion:The larger the total surface area per volume ratio / the smaller the size of cube, the faster the rate of diffusion.

Hypothesis is accepted.