The 5th Grade Performance Expectations (PEs) are organized into four different bundles of PEs in this model, using a topical arrangement. Bundle 1 focuses on physical and chemical changes in matter. Bundle 2 builds on Bundle 1 to focus on energy and matter flows in ecosystems. Bundle 3 extends this study to focus on larger Earth systems and how they affect one another. Bundle 4 shifts the scale to the immensely large, as students build understanding of space systems.