This document, created by Pennsylvania State University and hosted by the Nanotechnology Applications and Career Knowledge Network, serves as a guide for a laboratory activity where students "synthesize colloidal gold nanoparticles from solution-phase precursors" and "use UV-vis spectrophotometry to measure changes in the color of the resulting colloidal suspension as an electrolyte is added." The lab guide includes objectives, an introduction to colloids, step-by-step directions to the lab activity itself, and post-lab questions to test student comprehension. In order to access and download this material, users must complete a free registration.