Iconic gestures that are ubiquitous in speech are integral to human meaning-making. However, few studies have attempted to map out the role of these gestures in science teaching. This paper provides a review of existing literature in everyday communication and education to articulate potential contributions of iconic gestures for science teaching. We then analyze the iconic gestures produced by one university professor during a semester-long organic chemistry module to exemplify the functions of iconic gestures in sharing abstract scientific concepts. These gestures were found to show vital information about size, relative position, and movement of particles. Implications for designing teaching environments are discussed in light of our claims and we propose that iconic gestures can illuminate aspects of abstract scientific meaning to present a more complete version of meaning than what speech can accomplish on its own.