Guided by a new framework, the NAEP science assessment was updated in 2009 to keep the content current with key developments in science, curriculum standards, assessments, and research. The 2009 framework organizes science content into three broad content areas. Physical science includes concepts related to properties and changes of matter, forms of energy, energy transfer and conservation, position and motion of objects, and forces affecting motion. Life science includes concepts related to organization and development, matter and energy transformations, interdependence, heredity and reproduction, and evolution and diversity. Earth and space sciences includes concepts related to objects in the universe, the history of the Earth, properties of Earth materials, tectonics, energy in Earth systems, climate and weather, and biogeochemical cycles. The 2009 science assessment was composed of 143 questions at grade 4, 162 at grade 8, and 179 at grade 12. Students responded to only a portion of the questions, which included both multiple-choice questions and questions that required a written response. In 2009, the average score of eighth-grade students in Colorado was 156. This was higher than the average score of 149 for public school students in the nation. The percentage of students in Colorado who performed at or above the NAEP "Proficient" level was 36 percent in 2009. This percentage was greater than the nation (29 percent). The percentage of students in Colorado who performed at or above the NAEP "Basic" level was 70 percent in 2009. This percentage was greater than the nation (62 percent). [For the main report, "The Nation's Report Card: Science 2009. National Assessment of Educational Progress at Grades 4, 8, and 12. NCES 2011-451," see ED515259.].