Investigation into osmosis in potato cells.

Essay by lizzyrose89 April 2004

download word file, 9 pages 3.0 1 reviews

Downloaded 76 times

Osmosis Coursework

Introduction to Osmosis

Osmosis is a special kind of diffusion. Diffusion is the movement of particles from a high concentration to a low concentration until they are spread out evenly. Osmosis is the passage of water molecules from a region of high water concentration to a region of low water concentration through a selectively permeable membrane.

How Osmosis Works

The diagram above shows how water molecules move through the selectively permeable membrane from the region of high water concentration to the region of low water concentration until the concentration is equal on both sides of the membrane.

Before Osmosis

After Osmosis

Osmosis in Plant Cells

Water moves from cell to cell in plants by osmosis. The cell membrane of a plant cell is selectively permeable. So if a cell containing a weak solution (lots of water) is next to a cell with a stronger solution (less water), water moves by osmosis from the weak to the strong solution, as shown.

To help me gather this information I used 'Biology for You' by Gareth Williams, and 'All About Biology' by Brian Beckett and RoseMarie Gallagher. I also used the website

Preliminary Tasks

As a class group we did two preliminary practical tasks to introduce osmosis and how it works.

The Osmometer

The first task demonstrated the process of osmosis. This apparatus is called an osmometer.



·Capillary tube

·Visking tubing bag

·Sugar solution

·Distilled water



We set up the equipment as shown below and observed the level of liquid in the tube for the next 10-15 minutes.


The liquid in the capillary tube rose steadily over the time we observed it.


The visking tubing is a selectively permeable membrane. This means it lets only some particles go through it. In this experiment...