This Activity introduces students to the unique properties of nanoscale materials through exploration of size-dependent optical properties of gold nanoparticles. Students first prepare a solution of gold nanoparticles. They then investigate the solution’s use as an electrolyte sensor by adding a non-electrolyte and a strong electrolyte, and observing any resulting color changes. This Activity provides an introduction to scientific notation and orders of magnitude by exposing students to nano-sized materials. The Activity also provides connections to topics such as electrolytes, complementary colors, and spectroscopy.
Adam D. McFarland, Christy L. Haynes, Chad A. Mirkin, Richard P. Van Duyne, and Hilary A. Godwin, J. Chem. Educ. 2004, 81, p544A.