After the reaction flask is cooled to room temperature,
subsequent characterization of the sol is readily achieved by
UV−vis spectroscopy. A laser pointer can also be used to
demonstrate the Tyndall effect for colloidal suspensions.23 If
available, more sophisticated methods, such as transmission
electron microscopy (TEM),3,11,14 scanning tunneling microscopy
(STM)24 or atomic force microscopy (AFM)11 could be
applied