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.
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 http://www.purchon.com/biology/osmosis.htm.
As a class group we did two preliminary practical tasks to introduce osmosis and how it works.
The first task demonstrated the process of osmosis. This apparatus is called an osmometer.
ÃÂ·Visking tubing bag
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...