If C is the concentration of the diffusing species at distance x from the source and time t, then according to Fick’s second law (assuming diffusion coefficient, D is constant):

Diffusion topics include: Diffusion mechanisms, influential factors, steady and non-steady state diffusion. Diffusion is the movement of particles, ions, molecules, and solutions from a region of higher concentration to a region of lower concentration. It's driven by a gradient in chemical potential or Gibbs free energy.  Some examples of diffusion include: Incense and perfume sticks Balloons filled with helium Tea sachets Soda and cold beverages Breathing Pollution of the air Mineral and biomolecule transport in plants and animals  Diffusion is slightly slower in liquids than in... Show more

Diffusion topics include: Diffusion mechanisms, influential factors, steady and non-steady state diffusion.

Diffusion is the movement of particles, ions, molecules, and solutions from a region of higher concentration to a region of lower concentration. It's driven by a gradient in chemical potential or Gibbs free energy. 

Some examples of diffusion include:
Incense and perfume sticks
Balloons filled with helium
Tea sachets
Soda and cold beverages
Breathing
Pollution of the air
Mineral and biomolecule transport in plants and animals 

Diffusion is slightly slower in liquids than in gases because the molecules in gases move more quickly. 
Facilitated diffusion is a type of passive transport that uses specialized proteins to help molecules move across a cell membrane. In this process, molecules can move down their concentration gradient without requiring any energy input from the cell. 
Osmosis is a specific type of diffusion. It involves the movement of solvent molecules from areas of low concentration to regions of high concentration through a semipermeable membrane. 

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