Bubble-particle interactions play an important role in many technological processes, e.g., in flotation. Although mineral flotation involves fine particles, this work focuses on the interactions between a small bubble and larger spherical particle and determining their collision efficiency. Based on the theoretical and experimental work, a simple relation for estimating the collision efficiency is proposed. The calculated efficiencies are compared to a large set of experimental data and are found to be in excellent agreement. (C) 2014 Elsevier Ltd. All rights reserved.