RES.TLL-004 | Fall 2013 | Undergraduate

STEM Concept Videos

Probability and Statistics

Diffusion and Fick's Law


This video uses a simple model to help students understand the fundamental difference between a regular and a random walk. The concept of a random walk is connected to diffusion and is used to explain the structure of Fick’s law. Finally, Fick’s Law is used to explain why wearing a coat is useful in the winter, to estimate diffusion times for biomolecules, and to understand why we need a circulatory system to efficiently transport oxygen throughout the body.

Learning Objectives

After watching this video students will be able to:

  • Describe the difference between regular and random walks.
  • Explain the structure of Fick’s law.

Funding provided by the Singapore University of Technology and Design (SUTD)

Developed by the Teaching and Learning Laboratory (TLL) at MIT for SUTD

MIT © 2012

It is highly recommended that the video is paused when prompted so that students are able to attempt the activities on their own and then check their solutions against the video.

During the video, students will:

  • Perform calculations to compare the first and second moments for a molecule making a regular and random walk on a one-dimensional number line.
  • Estimate the time for a neurotransmitter to diffuse across a synaptic cleft.
  • Estimate the time for an oxygen molecule to diffuse from the lung to a leg muscle.