Résumé
I'll review recent experiments on the slow dynamics of colloidal hard spheres, a model system for the glass transition, and other soft materials, where particle interactions and/or high particle concentration lead to jamming. I'll describe new scattering methods to investigate not only the average dynamics, but also their spatial and temporal fluctuations. In particular, I'll show that while in colloidal hard spheres spatial correlations of the dynamics increase only modestly on approaching the glass transition, in other jammed materials the slow dynamics are correlated over macroscopic length scales.