Description:The demonstration has a large number of small ball bearings that can flow through a narrow opening and be scattered over a wider area. First, tilt device so that balls roll into top region. Then place the device on the face of overhead projector; the elevated legs give it a slope that allows the balls to roll into troughs, with approximately the characteristic Gaussian distribution.
It can be interesting to have the class discuss how changes to the environment (tilting the projector, shaking the apparatus, etc.) can change the distribution.