Aluminum and Teflon cylindrical particles with flat ends are dropped in aqueous Polyox solutions. The terminal equilibrium orientation of the particles is characterized by the tilt angle, a, formed by the major axis of the cyl-inder with the horizontal. It is observed that a is a function of the aspect ratio L=L/d, where L is the length and d is the diameter of the cylinder, and that it varies continuously from a certain angle, a0, to 90, as L increases toward a value L0. For a given shape, both a0 and L0 depend on the density of the cylinder and the properties of the liquid used. For the particles we have considered the value of L0 is of the order of 2. This 搕ilt-angle phenomenon?disappears as soon as the ends of the cylinder are round. Specifically, cylinders of the same density and with the same aspect ratio but with round ends, when dropped in the same polymeric solution will reach a final orientation with a=90. Therefore, this tilt-angle phenomenon seems to be tightly related to the shape of the particle.
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