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Understanding experimental design (e.g. control of variable strategy or CVS) is foundational for scientific reasoning. Previous research has demonstrated that demonstrations with cognitive conflict (e.g. asking students to evaluate and explain different experimental designs) are effective in promoting children’s scientific reasoning, however, the implementation of this approach often requires significant instructional time and resources. This study reports the impact of a brief, scalable intervention on one component of scientific reasoning, understanding experimental design, by providing brief instruction on the control-of-variable strategy (CVS), embedded in a food science activity (popping popcorn). Threehundred and seven (307) 3rd-5th graders in the midwestern US participated in either a CVS intervention or a demonstration on the science of popcorn without a CVS intervention. Performance on a pre-activity test (involving identification of good and bad experiments) did not differ between conditions. By contrast, postactivity performance was significantly greater for classes who received the CVS intervention. Thus, a brief discussion of the CVS embedded within a food-science demonstration can have a meaningful impact on children’s understanding of conducting a quality experiment. Our results demonstrate the efficacy of a simple, low-cost intervention for CVS that is potentially scalable. 

Everyday activities such as cooking a meal are natural opportunities for “challenging” family talk, which promotes cognitive development by prompting explanations and elaborations. Our study investigates a light intervention to increase the frequency of challenging family STEM talk during an everyday activity. Sixty-two families with children (mean age = 9.49) recorded their conversations while popping popcorn using either a standard recipe or a recipe with embedded wh-question prompts (e.g., Why did some kernels not pop?). Conversations were transcribed and coded to measure four qualities of challenging STEM talk: STEM words, STEM explanations, spontaneous questions, and elaborations (or interactive turn-taking). The results demonstrate that families who received wh-question prompts embedded into the recipe produced 3–5 times more instances of challenging STEM talk than families who received no prompts. These results provide evidence for a light intervention that increases family STEM talk through a familiar, everyday activity.