Assessment tasks intended to support teaching and learning in classrooms that are enacting NGSS-aligned instruction, and to gain insights into grades 3-8 students’ progress in building proficiency with NGSS performance expectations (PEs). The tasks are designed to increase access and engagement for students with a range of ethnic and cultural backgrounds, linguistic abilities, and learning differences. The tasks include web-based tools to integrate computational models, which students can manipulate to explore phenomena, to generate data for a scientific argument, or to carry out an experiment. Teachers can select tasks to use with their students and assign them to be completed individually, in small groups, or during whole class instruction. As students complete the assessment tasks online, teachers can monitor student progress in real-time. The assessment portal links scoring rubrics to tasks to help teachers understand and evaluate which aspects of student work show progress toward mastery of the targeted 3-D integrated knowledge. Using these rubrics, teachers can provide online feedback to individual students.