Changes

==Introduction==

==Introduction==

If gases or liquids are unevenly distributed, this inequality will be corrected by the movement of molecules from the region of high concentration to that of low.  This is achieved by the process of diffusion. This works by the random '''thermal movement''' of molecules.  If there is a gas present in an air tight room and then a door is opened into the next room the laws of probability state that some of the randomly moving molecules will escape through the door into the adjoining room and that eventually the concentrations in both rooms with be approximately the same.  In the period between the door opening and the rooms having the same concentration net movement will be from the original room to the new room. This is because as there are more molecules in the original room there is an increased chance that these molecules will leave the room; and as there are few molecules in the second room there is a slim chance that they will move into the first room.

If gases or liquids are unevenly distributed between two areas.  One area having a higher concentration than the other then the differance between those two areas is termed the '''concentration gradient'''.  The equality is then corrected by the movement of the molecules down this so called gradient from the region of high concentration to that of low.  This process is '''passive''' as the molecules do not have to be forced to do this and it is reffered to as '''diffusion'''.

 

 

This works by the random '''thermal movement''' of molecules.  If there is a gas present in an air tight room and then a door is opened into the next room where a lower concentration of the same gas is present the laws of probability state that more of the randomly moving molecules will escape through the door from the area of high concentration than will escape back through the door from the area of low and that eventually the concentrations in both rooms with be approximately the same.  The net movement therefore will be from the room with a high concentration to that of a low concentration.

==Ficks Law==

==Ficks Law==