The preschool years are an important time in the development of understanding the property of weight. This experiment investigates whether social learning, specifically imitation, will promote preschoolers’ use of this property. Children were randomly assigned to one of three groups. Those in the experimental group saw an adult sort four objects based on their weights. Children were then presented with the objects. Whether children sorted these objects based on their weights was scored, as was their sorting of a novel set of objects (to assess generalization) and their imitation of the hefting gestures used by the adult. Comparisons to control groups indicated that 4-year-olds, but not 3-year-olds, benefitted from the modeling and sorted by weight. These results suggest that social learning is an effective way to promote children’s use of this invisible property.