I would like to try this experiment:
Monitoring Particle Growth: Light Scattering Using Red and Violet Diode Lasers, by Heejoon Ahn and James E. Whitten
Journal of Chemical Education Vol. 82 No. 6 June 2005
Basically it is a way to monitor the production of colloids by sodium thiosulfate and hydrochloric acid, and see how the scattering of red light and violet light is different at different particle sizes.
I will try and keep you updated as I go.