In this paper we investigate the hypothesis that when bubbles carrying attached hydrophobic particles arrive at an air-liquid interface, the abrupt change in velocity is sufficient to dislodge attached particles, which fall back into the liquid. For the first time, experiments have demonstrated a case in which the particles do not detach, but move smoothly over the surface of the bubbles. The kinetic energy of arrival is dissipated by the motion of the particles through the liquid, as they move over the surface of the bubble while remaining attached. Some energy is also dissipated by the pulsations of the bubbles. The pulsations themselves do not lead to detachment of particles. A theory has been developed to explain the observed phenomena. (C) 2014 Elsevier B.V. All rights reserved.