While on a vacation flight from Hawaii to California, I observed sunset occurring on clouds far below. The view triggered a vague memory about a fun article 1 published more than three decades earlier on the topic of "Doubling Your Sunsets." Simple observations from my flight made it possible to compute the Earth's radius.

This is the fourth paper in a series of four. The first paper in the series, "Vacuum Energy and Inflation: 1. A Liter of Vacuum Energy" [EJ1024183] discusses an example of vacuum energy. Vacuum energy is explained as an energy with a negative pressure whose energy density remains constant in an expanding space. Paper 2, "Vacuum…

The motion of a candle flame in front of a loudspeaker has been suggested as a productive demonstration of the longitudinal wave nature of sound. The demonstration has been used also as a research tool to investigate students' understanding about sound. The underpinning of both applications is the expectation of a horizontal, back-and-forth…

In a recent paper, Zable described an experiment with a near-spherical balloon filled with impure helium. Measuring the temperature and the pressure inside and outside the balloon, the lift of the balloon, and the mass of the balloon materials, he described how to use the ideal gas laws and Archimedes' principal to compute the average molecular…

Atwood's machine is used in countless introductory physics classes as an illustration of Newton's second law. Initially, the analysis is performed assuming the pulley and string are massless and the axle is frictionless. Although the mass of the pulley is often included when the problem is revisited later in the context of rotational dynamics, the…

Conceptual Change is a widely accepted theoretical framework for science education. Setting up successful learning and teaching arrangements in this framework necessarily entails including students´ preconceptions into the construction of those arrangements. In order to provide a basis for such arrangements this study investigated and explored…

This article considers what might be taught to meet a widely held curriculum aim of students being able to understand research in a discipline. Expertise, which may appear as a "chain of practice," is widely held to be underpinned by networks of understanding. Scientific research expertise is considered from this perspective. Within…

The study reported here investigated experienced teachers' views on several nature of science (NOS) issues 2 to 5 years after they completed a demanding secondary science teacher education program in which the NOS was an extensive and recurring component. Both quantitative and qualitative data were collected and analyzed to determine study…

Reading the interesting article "Discerning selective traditions in science education" by Per Sund, which is published in this issue of "CSSE," allows us to open the discussion on procedures for teaching science today. Clearly there is overlap between the teaching of science and other areas of knowledge. However, we must…

When designing a chemistry education research study it is important that the researcher select or create assessment instruments and methodologies that are valid. This ensures that correct interpretations can be made from the data collected using the instrument or methodology. The two studies described here introduce a novel method for…

A project-based biophysical chemistry laboratory course, which is offered to the biochemistry and molecular biology majors in their senior year, is described. In this course, the classroom study of the structure-function of biomolecules is integrated with the discovery-guided laboratory study of these molecules using computer modeling and…

In the modern physics unit included in the course curriculum of grade 10 physics introduced in the 2007-2008 education year, the aim is that students at this grade level are aware of any developments which constitute modern physics and may be considered new, and interpret whether mass, length and time values of the motions at any velocities close…

A 1 h classroom activity is presented, aimed at consolidating the concepts of microstates and Russell-Saunders energy terms in transition metal atoms and coordination complexes. The unconventional approach, based on logic and intuition rather than rigorous mathematics, is designed to stimulate discussion and enhance familiarity with quantum…

This study presents an analysis of alternative conceptions (ACs) on acid--base chemistry harbored by grade 9 students in Singapore. The ACs were obtained by the development and validation of a 4-tier diagnostic instrument. It is among the very few studies in the science education literature that have focused on examining results based also on…

Pedagogical practitioners who emphasise active learning in undergraduate chemistry courses widely use the Student Assessment of Learning Gains (SALG) instrument to measure students' perceptions of their gains in knowledge and skills in chemistry. Although numerous studies have reported SALG results in support of successful pedagogical…