Fick's Law of Diffusion Calculator
Calculate diffusion rates using Fick's Law with our advanced calculator designed for life and earth sciences.
How to use
Provide the concentration gradient and diffusion coefficient, then click Calculate. The calculator shows the diffusion flux direction by keeping the negative sign from Fick's Law and reports the magnitude for quick comparisons.
Methodology
Fick's First Law states that diffusion flux equals −D times the spatial concentration gradient. The negative sign indicates motion from regions of high concentration to low concentration.
- Keep the diffusion coefficient positive; it describes how freely molecules move through the medium.
- The concentration gradient may be positive or negative depending on the chosen coordinate orientation.
- All values are rounded to two decimals or shown in scientific notation when very small.
Full original guide (expanded)
This calculator is tailored for students and professionals in life and earth sciences to illustrate mass transfer rates.
Data and equations follow ChemEnggCalc's Fick's First Law reference.
J = -D · (dc/dx)
Example: Gradient = 0.1 mol/m³, D = 1.0e-9 m²/s results in J = -1.0e-10 mol/(m²·s), signaling flux down the gradient.
Glossary
- dc/dx: Change in concentration per unit distance.
- D: Diffusion coefficient, typically >0.
- J: Diffusion flux (mol/(m²·s)).
FAQ
Why is my diffusion rate negative?
The negative value indicates the flux direction is toward decreasing concentration.
Can this handle gases?
Yes, the law applies to gases, liquids, and solids alike.