Color My Nanoworld

Abstract

In this activity, students are introduced to the unique properties of nanoscale materials. The activity begins with the synthesis of 13 nm-diameter gold nanoparticles by reduction of a gold salt. The students use the resulting nanoparticle solution to explore the size-dependent optical properties of gold nanoparticles. Specifically, they determine that the nanoparticle solution functions as an electrolyte sensor because electrolyte-induced aggregation of the nanoparticles results in a dramatic color change.