Science in the Lower School is designed to help students, through inquiry, to continually build on their abilities and revise their knowledge stemming from their curiosity about the immediate environment and their initial conceptions about how the world works. The goals for the program are to provide students with engaging hands-on opportunities and experiences to guide them toward a more scientifically based and coherent view of the Earth, space, life and the physical sciences. In the Lower School, science involves integrating engineering and technology to provide a context in which students can test their own developing scientific knowledge and apply it to practical problems.

The performance expectations in third grade help students formulate answers to questions. They learn to analyze and interpret data and use this as evidence to engage in argument. The science curriculum for third grade explores the variations in traits of different organisms and the factors in changing environments that affect survival today and in the past. Students quantify and predict weather conditions in different areas and at different times. They learn to organize and use data to describe typical weather conditions and make claims about the merit of a design solution that reduces the impacts of severe weather. Students investigate the effects of balanced and unbalanced forces on motion and the cause and effect relationships of electric or magnetic interactions between two objects not in contact with each other. They are then able to apply their understanding of magnetic interactions to define a simple design problem that can be solved with magnets.