Calculate diffusion time, distance, or diffusion coefficient, including film half-time, from any two inputs with selectable units and material presets.

One-dimensional RMS displacement with constant diffusivity. This is not a guaranteed arrival time.

Approximate dilute-water values at 25 ยฐC, except hemoglobin at 20 ยฐC. Use measured D for other conditions.

Diffusion Time Formula

The following formula gives a one-dimensional characteristic diffusion time for an RMS displacement, with constant diffusivity and no drift or boundaries. It is not a guaranteed arrival time. Film mode instead estimates the time for a 50% change in average concentration in a uniform slab exposed on both faces, using its full thickness.

T = (dยฒ) / (2 ร— D)

Variables:

  • T is the diffusion time (s)
  • d is the distance to be covered (m)
  • D is the diffusion coefficient (mยฒ/s)

To calculate the diffusion time, square the distance to be covered. Then, multiply the diffusion coefficient by 2. Divide the first result by the second result to get the diffusion time.

What is Diffusion Time?

Diffusion time refers to the period it takes for particles, molecules, heat, or other entities to spread out or move from one area to another through the process of diffusion. This process is influenced by factors such as the medium’s properties, the distance to be covered, and the size of the particles. In physics and chemistry, it’s a crucial concept that helps in understanding how substances mix or react with each other.

How to Calculate Diffusion Time?

The following steps outline how to calculate the Diffusion Time using the given formula:

  1. First, determine the distance to be covered (d) in meters.
  2. Next, determine the diffusion coefficient (D) in square meters per second (mยฒ/s).
  3. Next, gather the formula from above: T = (d^2) / (2 * D).
  4. Finally, calculate the Diffusion Time (T) in seconds.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge:

distance to be covered (d) = 10 m

diffusion coefficient (D) = 5 mยฒ/s