As teachers make the transition to inquiry-centered science, they discover a need for new assessments. In response to this need, a group of 125 elementary teachers embarked on a three-year investigation of science assessment. This project was a component of the professional development provided by the Partnership for Systemic Change, which includes the Rahway, Linden, and Readington Township Public Schools in New Jersey; the North Penn School District in Pennsylvania; and the Merck Institute for Science Education. The following examples include assessments that teachers designed to determine whether students were achieving the K–4 earth materials standards.