Chemistry students are often introduced to the concept of reaction rates through demonstrations or laboratory activities involving the well-known iodine clock reaction. For example, a laboratory experiment involving thiosulfate as an iodine scavenger is part of the first-year general chemistry laboratory curriculum at Dalhousie University. With…

This article reports on a design study aimed at achieving that students experience their learning as meaningful. Two conditions for meaningful activities were identified: (1) students should be motivated to attain a certain goal and (2) they should have rudimentary conceptual and procedural knowledge of how to attain that goal. Together, these…

The "What's the "matter" With XOD" activity addresses students' misconceptions and refines their ideas about phases of matter. This activity introduces the characteristics for solids, liquids, and gases, and begins a discussion about physical and chemical changes and how matter can cycle through different phases. Depending on class size and…

Recent reports have begun to lay the foundation for a re-visioned K-8 science curriculum which includes four strands that could be used to define and assess science proficiency for all students. Using these strands as an analytic lens, this pre-post multiple-case case study explores elementary school science teachers' practices and their students'…

The national Science, Technology, Engineering, and Math (STEM) Education Initiative favors a curriculum shift from the compartmentalization of math and science classes into discrete subject areas to an integrated, multidisciplinary experience. Many states are currently implementing programs in high schools that provide greater integration of math,…

This article presents an analysis of the longitudinal consequences of out-of-school science learning with a conceptual framework that connects the intentions of youth to their participation in science. The focus is on one girl's science activities in her home and hobby pursuits from fourth to seventh grade to create an empirical account of how…

Students' difficulties with accurately conceptualizing the relationships among the Earth, Moon, and Sun are well documented. Any teacher who has seen the film "A Private Universe" (Schneps and Sadler 1988) will remember the challenge the interviewees experienced when trying to explain their understanding of this phenomenon. This paper describes a…

Ten adolescent judokas performed circuit training consisting of six 40-s periods of judo exercises separated by 40 s (CT1:1), 120 s (CT1:3), or 200 s (CT1:5) of rest. Heart rate, blood lactate concentration, and the number of repetitions were recorded. Heart rate reached [approximately]180 beats[middle dot]min-1 at the end of work periods, with…

This article features Boulder Journey School, located in Boulder, Colorado, a full-day, year-round school that welcomes over 200 young children, ages 6 weeks to 6 years, and their families. The school community is committed to a culture based on children as curious and competent individuals capable of coconstructing knowledge. In Boulder Journey…

One of the difficulties in teaching 20th-century physics ideas in introductory physics is that many seminal experiments that are discussed in textbooks are difficult or expensive for students to access experimentally. In this paper, we discuss an analogous exercise to Millikan's oil-drop experiment that lets students experience some of the physics…

Motion is a topic that is taught from elementary grades through to university at various levels of sophistication. It is an area that can be challenging for learning in a conceptually meaningful way, and formal kinematics instruction can sometimes seem dry and boring. Thus, the nature of students' initial introduction to motion is important in…

The quality of drinking water has been gaining a great deal of attention lately, especially as water delivery infrastructure continues to age. Particles of various metals such as lead and copper, and other substances like radon and arsenic could be entering drinking water supplies. Spilled-on-the-ground hydrocarbon-based substances are also…

A significant issue associated with ethanol-gasoline blends is the phase separation that occurs with the addition of small volumes of water, producing an ethanol-deficient gasoline layer and an ethanol-rich aqueous layer. The gasoline layer may have a lower-than-desired octane rating due to the decrease in ethanol content, resulting in engine…

Scientific modeling is an integral part of contemporary science, yet many students have little understanding of how models are developed, validated, and used to predict and explain phenomena. A simple modeling exercise led to significant gains in understanding key attributes of scientific modeling while revealing some stubborn misconceptions.…

A reference electrode is one of the prerequisites of electrochemical investigations. Many electrodes are commercially available but are expensive and prone to accidental breakage by students. Here we report a simple, easy-to-fabricate, inexpensive, reliable, unbreakable, and reproducible Ag/AgCl reference electrode. The empty barrel of a…