Young students are introduced to the complex systems of the Earth through numerous lessons on its natural resources, processes, weather, climate and landforms. Key earth science topics include rocks, soils and minerals, water and natural resources, weather patterns and climatic regions, wind, erosion, landforms, and the harvesting of fossil fuels-all presented from an engineering point-of-view. (See the Unit Overview section for a list of topics by lesson.) Through many hands-on activities, students build and test sand castles for construction strength, measure snow melt as a potential water source, use colored ice cubes and salt water to learn about ocean currents, make 3-D water catchment basins, make surface tension/surfactant-powered paper boats, build and use wind vanes, build and test model wind turbines, model and observe five types of erosion, model acid rain using chalk and kitchen supplies, build transportation systems across their own 3-D model landscapes, take core samples from a clay model of the Earth's crust, read and create graphs and charts as they learn about international oil production and consumption, act as engineers by specifying the power plants to build for communities, given scenarios with budgets, energy needs and environmental impacts. They learn the steps of the engineering design process as they hypothesize ways engineers might obtain water for communities facing water crises.