GJM1021Marko the Pencil makes it easy to understand and remember science concepts. Learn about the Solar System, weather, the water cycle, geology, properties of minerals, volcanoes, plate tectonics, weathering, topography, erosion, energy resources, and energy conservation. An excellent tool to prepare for any earth science test. Meets National Science Education Standards. Approx. 61 min. Grades 3-8.