Diffusion is a truly interdisciplinary topic bridging all areas of STEM. Through statistical notions of the random walk, physics brings a unique, stochastic perspective to diffusive processes as first shown by Einstein's Nobel-Prize-winning work on Brownian motion. We present a hands-on educational activity for introductory physics students illustrating diffusion as a random walk. The random-walk activity, data collection and analysis techniques will be presented. Pre- and Post-testing demonstrates that the activity and analysis improves student understanding of the mechanisms underlying diffusion.