In an age where getting an answer is as easy as a well-chosen phrase typed into a search engine, it is important for teachers to be more interested in "how" students know, rather than "what" students know. In the sea of available information today, students must provide answers based on evidence. A student's ability to explain…

Avogadro's conception of the structure of gases was not widely accepted by his contemporaries--probably because the hypothesis was not supported by direct evidence. This problem is rarely addressed in schools. This article discusses the difficulties that accompany the acceptance of new ideas. Such difficulties may be associated with the ways in…

This study developed learning progression-based measures of science teachers' content knowledge (CK) and pedagogical content knowledge (PCK). The measures focus on an important topic in secondary science curriculum using scientific reasoning (i.e., tracing matter, tracing energy, and connecting scales) to explain plants gaining weight and…

This research study is an investigation of student-laboratory (i.e., lab) learning based on students' perceptions of experiences using questionnaire data and evidence of their science-laboratory performance based on paper-and-pencil assessments using Maryland-mandated criteria, Montgomery County Public Schools (MCPS) criteria, and published…

Understanding how DNA banding patterns in a gel can aid in the conviction or exoneration of suspects and be utilized for positive identification of biological fathers in paternity cases can be intimidating. In reality, the logistics and technology used in such cases are rather straightforward. This exercise is designed for use in high school…