Recent reforms of science curricula emphasize problem solving and conceptual understanding rather than knowledge of facts and formulas. Many educators argue for a corresponding change in testing. Specifically, multiple-choice tests, the traditional measures of achievement, should be replaced by assessment methods such as hands-on science exercises and other performance-oriented tasks that are better suited to measuring conceptual understanding and problem-solving ability. This report documents the hands-on science tasks and scoring guides that were developed as part of a RAND study of the technical quality and feasibility of science performance assessment in large-scale testing programs. The document contains a complete description of each of the 12 tasks used in the study, including the task blueprint (or "shell") from which the task was developed, the task booklet, photographs or copies of all the equipment and apparatus that accompanied the task, and the task scoring guide. The information should interest researchers who want to use these tasks in other studies and policymakers who want to understand more about using performance exercises for assessment at the local level.