Pulsed Gradient Spin Echo (PGSE) DOSY is a NMR technique used for determining the hydrodynamic radius of a molecule in solution by measuring the rate of diffusion. This technique requires a standard, usually tetrakis(trimethylsilyl)silane (TMSS). This activity will cover the basics of how PGSE works and includes built in animations to demonstrate how the nuclear magnetization is affected. Each slide has comments explaining the content for the user's convenience.