This paper begins with an early measurement of the speed of sound in water. A historical overview of the consequent development of SONAR and medical imaging is given. A method of measuring the speed suitable for demonstration to year 10 students is described in detail, and an explanation of its systematic error examined.

Poly(vinyl alcohol) (PVA) precipitates in many kinds of aqueous salt solutions. While sodium sulfate, a coagulant for PVA fiber, precipitates PVA to yield a white rigid gel, coagulation of PVA with aluminum sulfate, a coagulant for water treatment, yields a slime-like viscoelastic fluid. One type of homemade slime is prepared under basic…

A small-scale wastewater cleaning plant is described that includes the key physical pretreatment steps followed by the chemical treatment of mud by flocculation. Water, clay particles, and riverside deposits mimicked odorless wastewater. After a demonstration of the optimization step, the flocculation process was carried out with iron(III)…

Dark matter makes up most of the matter in the universe but very little of a standard introductory physics curriculum. Here we present our construction and use of a spandex sheet-style gravity simulator to qualitatively demonstrate two aspects of modern physics related to dark matter. First, we describe an activity in which students explore the…

When readers search for misspellings in a proofreading task or for a letter in a letter detection task, they are more likely to omit function words than content words. However, with misspelled words, previous findings for the letter detection task were mixed. In two experiments, the authors tested the functional equivalence of both tasks. Results…

In the present paper we suggest an original physical explanatory model that explains the mechanism of the sound amplification process in a stethoscope. We discuss the amplification of a single pulse, a continuous wave of certain frequency, and finally we address the resonant frequencies. It is our belief that this model may provide students with…

Thin film interference manifests itself in a wide range of visually pleasing situations in everyday life (in the colored effects caused by a drop of oil on water, in soap bubbles, etc.) and is also involved in important technical applications (semi-reflecting mirrors, anti-reflection lenses, etc.). Yet, despite its familiarity, high school…

When conducting experiments involving the measurement of physically related quantities, choosing an appropriate spacing for the experimental independent variable is a crucial procedure whose consequences may go beyond data graphical visualization. This is particularly true if the measured quantities are nonlinearly related and experimental errors…

Laboratory-based instruction is a powerful educational tool that engages students in Science, Technology, Engineering and Mathematics (STEM) disciplines beyond textbook theory. This is true in mechanical engineering education and is often used to provide collegiate-level students a hands-on alternative to course theory. Module-based laboratory…

Design integrates concepts and solves problems. Crowdsourcing design imports vast knowledge and produces creative ideas. It publishes design tasks, collects dozens of contributors' ideas and reward the best. Contributors in crowdsourcing design work individually when generating ideas. However, those who collaborate could make better use of crowd's…

Twenty-two hundred years ago, the Greek scientist Eratosthenes measured the circumference of the Earth. This paper describes an experiment to replicate Eratosthenes' experiment with observers located in Australia and New Zealand. The most accurate circumference produced in the experiment described in this paper is 38,874?km, measured at Rosebud,…

We often say that food and fuels "contain" energy, whereas energy is stored in the fuel-oxygen system generated during photosynthesis. This article suggests revised approaches to teaching that make a clear distinction between matter (food, fuel, oxygen) and energy. (Contains 1 table, 5 boxes, and 6 figures.)

In science education research, there is a growing body of studies focusing on the role of multiple representations in pupils' learning. This study is based on a social semiotic perspective and in the analysis, there is a special focus on how the content is conveyed and how relations are created through interaction between teachers/pupils and the…

Physics lab instruction is evolving in response to changing technology, a desire to better prepare students for diverse careers, and renewed focus from physics education researchers. To prepare researchers to evaluate progress in instructional labs in the future, this study set out to understand the current state of instructional physics labs in…

New and emerging digital technologies are making an impact on how we practice science, and this has implications on how we teach science. We introduce the concept of the Electronic Laboratory Notebook (ELN) as used in the research environment and describe how we have implemented this as a tool for providing undergraduate science students with an…