Filled with high interest exercises, this Grade 4 Unit 9workbook focuses on the atmosphere, the hydrosphere, the lithosphere, rotation and revolution. Lifepac science curriculum brings the physical world of God's creation into focus. Students conduct experiments to reinforce scientific concepts, such as the planet earth. Perfect for students who flourish in a self-paced, individualized learning format, each consumable Lifepac combines lessons, exercises, projects, reviews, and tests. Paperback.