Threshold concepts are essential ideas about the natural world that present either a barrier or a gateway to a deep understanding of science. Weight, mass, and gravity are threshold concepts that underpin students' abilities to understand important ideas in all fields of science, embodied in the performance expectations in the Next Generation…

Purpose: The authors created a database of expository oral language samples with the aims of describing the nature of students' expository discourse and providing benchmark data for typically developing preteen and teenage students. Method: Using a favorite game or sport protocol, language samples were collected from 235 typically developing…

This study was undertaken to explore whether incest, extrafamilial sexual abuse, and physical abuse are linked with different psychological or behavioral consequences, and whether abuse affects males and females differently. In 1989, a survey instrument was administered to all 6th, 9th, and 12th graders in 84% of all the public schools in…