Rate of Osmosis Between Potato Cylinders and Sucrose Solution

Rate of Osmosis Between Potato Cylinders and Sucrose Solution

Introduction

I am doing an investigation, to find out on how varying one factor

effects the rate of osmosis between potato cylinders and Sucrose

solution.

Osmosis is the diffusion of solvent (usually water) particles through

a selectively permeable membrane from a region of high solvent

concentration to a region of lower solvent concentration.

Examples of Selectively permeable membranes are (a) the cell membrane,

and (b) visking (dialysis) tubing. Such membranes are thought to have

tiny pores that allow the rapid passage of small water particles, but

restrict the passage of larger solute particles.

Since the membrane is Selectively permeable, Osmosis is important in

the passage of water into and out of cells and organisms, and depends

on Osmotic pressure.

Osmotic pressure

================

The pressure exerted by the osmotic movement of water that can be

demonstrated in an Osmometer. Water moves into the solution in the

visking bag by Osmosis, causing the liquid level in the tube to rise.

Osmotic pressure depends on the relative solute concentrations of the

solution s involved. The Osmotic pressure that a solution is capable

of developing is called its osmotic potential, but is only realised in

an Osmometer.

Cell membranes

==============

All living things have certain requirements they must satisfy in order

to remain alive. These include exchanging gases (usually CO2 and O2),

taking in water, minerals, and food, and eliminating wastes. These

tasks ultimately occur at the cellular level, and require that

molecules move through...

... middle of paper ...

...better line on my graph,

which will enable me to show what happens as the surface area and rate

of osmosis increase. The surface areas that I will use in my

experiment will be:

1. 17.3cm²

2. 18.8cm²

3. 19.8cm²

4. 22.0cm²

5. 23.6cm²

6. 27.3cm²

7. 28.8cm ²

8. 29.8cm²

9. 32.0cm²

10. 37.3cm²

As you can see, I have a wide range as the surface area ranges from

17.3cm² to 37.3cm². Therefore, the surface area is over double from

what it started out as. This wide range will give me points on the

graph that aren't cramped together, but nicely spread out so that I

can draw a line of best fit.

Secondary sources

- Key Science Biology by David Applin (pages 143-144)

- GCSE Biology revision guide by 'The Science Co-ordination group'

(page 5)

- Microsoft Encarta