MathBench > Cellular Processes


General Transport Equations and Fick's First Law

Before we move from Fick’s First Law to his (creatively named) Second Law, it is worth noting that Fick's Law is really just one of several “transport equations” that all have a common form. In these equations, J stands for transport (don’t ask me why). So you can see that the same equation that we have been learning about is applicable in almost the exact same form in several different fields!



where D is the diffusion coefficient, C is the concentration of particles and x is the distance.

For Charge


where V is voltage, so the flux of ions is directly proportional to the difference in voltage (the voltage potential). As in the diffusion equation, K is a coefficient that relates to the medium the charge is traveling through.

For Energy (heat)


where T is temperature (Kelvin), so that heat transfer is directly proportional to the difference in temperatures. K is the same as above.