It is fascinating to listen to middle school students talk about food for plants and animals and how that food is used. Some students describe ideas that are essentially correct. Some comments suggest that students are familiar with the content, but their understanding is incomplete or includes inaccuracies. Finally, some students have little…

Through a project funded by the National Science Foundation, Horizon Research has been developing assessment items for students (in the process, compiling item-writing principles from several sources and adding their own). In this article, the authors share what they have learned about writing items that reveal student understanding, including…

Giant exploding volcanoes...asteroids crashing into Earth...continents floating across the oceans...massive pools of lava...violent earthquakes splitting continents--middle school students hold a variety of ideas about Earth, how it has changed over time, and what has caused these changes. Listening to students talk about how the world works is…