The primary purpose of this study was to examine the efficacy of the elaborative conversation strategies (ECS) intervention in improving the quality of parents' science talk during everyday home learning interactions using a single-case experimental design. Specifically, the study explored whether training parents in ECS could increase their use of these high-quality conversation strategies and enhance the quality of their science talk when engaging their children in science activities. The study also investigated how the ECS intervention impacted children's science knowledge, skills, and interest, as well as parents' attitudes toward supporting their children's science learning. Participants included five typically developing preschool children and their primary caregiver. All children attended the local Educare program serving low-income families. The study used a single-case experimental design that included multiple assessment points (15 home visits per family), including pre- and post-assessments, three baseline, five intervention, and five follow-up/probe assessments. The efficacy of the ECS intervention was evaluated using visual analyses that examined the level, trend, and stability of the data over time as well as effect-size measures. The findings revealed that the ECS intervention had a small to moderate effect on most parents' use of ECS and some parents' engagement in high-quality science talk. Parents who received the ECS training also demonstrated more positive attitudes toward supporting their children's science learning compared to before the intervention. Additionally, most children showed improvement in their science knowledge following the intervention, although there was a slight decline in children's interest in science after the ECS intervention. This study addressed critical aspects of high-quality parent-child interactions related to children's early science learning. The findings highlighted the value of high-quality conversation strategies that parents can use in everyday interactions to support their children's science learning. Moreover, the study underscored the importance of equitable access to enriching science learning opportunities for low-income families and empowered parents to engage their children in meaningful, science-focused interactions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]