This document presents a two-part study. In the first part, open-ended questions based on interview studies were administered via paper-and-pencil tasks to 76 sixth and eighth grade students. In the second part, the earth and sun relationship questions were extracted, modified, and given to 178 seventh grade students. In part one, the performance of the students on the earth orientation tasks was compared to the performance of students in previous cross-age studies and no significant difference was detected between the two groups. In part two, an analysis of pretest results showed differences between the ability-grouped classes, but not for non-ability-grouped classes. Post-test analysis showed significant increases in the overall scores of the instructed classes. An analysis of covariance showed no differences between the gains of the students in different schools or the classes of different abilities. It was concluded that the instrument developed was a reliable means of eliciting and assessing student concepts in earth science. Statistics describing individual items and the overall test are included. Copies of versions of the test and instructions for coding the answers are included. (CW)