  We study a colloidal suspension confined between two quasi-parallel walls as
a model system for glass transitions in confined geometries. The suspension is
a mixture of two particle sizes to prevent wall-induced crystallization. We use
confocal microscopy to directly observe the motion of colloidal particles. This
motion is slower in confinement, thus producing glassy behavior in a sample
which is a liquid in an unconfined geometry. For higher volume fraction samples
(closer to the glass transition), the onset of confinement effects occurs at
larger length scales.
