We report the peculiar impact properties of small spherical shells fil
led with a viscous liquid. Upon collisions of two identical Liquid-fil
led shells, the fluid is progressively set in relation by the shell sp
in induced by tangential impact forces. An analysis of the correspondi
ng fluid motion predicts a collision outcome unlike that of solid sphe
res where angular velocity is uniform, Observations of colliding vitam
in-E pills reveal that the point of contact is rarely involved In gros
s slip. In the direction of the line of centers, collisions are adequa
tely described by a kinematic restitution coefficient. In the perpendi
cular direction, they generally exhibit rolling contact. (C) 1997 Amer
ican Institute of Physics. [S1070-6631(97)00512-6].