Over the past 10 years our AST group in has partnered with teams of secondary science teachers. These teachers have revised curriculum to be more aligned with NGSS and the AST practices. This page includes AST Curriculum Starters. These are not full units of instruction, but rather starting ideas for how topics typically taught in K-12 can be revised. Included in the documents are a puzzling phenomenon, a scientific explanation, a list of NGSS Standards, a summary table, and model template. We invite you to use these, design and share tools related to these units, and to propose your own curriculum starters.