An experiment analogous to that devised by Grimaldi and subsequently repeated by Young to study the nature of light has been realized with electrons. Following the Grimaldi and Young line of thought, an original approach is presented to introduce undergraduate physics students to the wave behaviour of electrons. An electron microscope equipped…

The solution to the Euler-Lagrange equation is an extremal functional. To understand that the functional is stationary at local extrema (maxima or minima), we propose a physics experiment that involves using a soap film to form a catenoid. A catenoid is a surface that is formed between two coaxial circular rings and is classified mathematically as…

A recent article by Morse described interesting electrostatics experiments using an MBL charge sensor. In this application, the charge sensor has a large capacitance compared to the charged test object, so nearly all charges can be transferred to the sensor capacitor from the capacitor to be measured. However, the typical capacitance of commercial…

The effect of density inversion on the convective flow of water in a spherical glass flask cooled with the help of an ice-water bath is shown. The experiment was carried out by temperature measurements (cooling curves) taken at three different heights along the vertical diameter of the flask. Flows inside the flask are visualized by seeding the…

In delivering chemistry courses by distance, a key challenge is to offer the learner an authentic and meaningful laboratory experience that still provides the rigour required to continue on in science. To satisfy this need, two distance general chemistry laboratory courses appropriate for Bachelor of Science (B.Sc.) students, including chemistry…

The main aim of this study was to examine how a group of elementary students perceived their engagement in a project-based science intervention investigating the water quality of a local lake. The students collaborated with a scientist to conduct various experiments and used handheld computers to collect and analyze data in order to examine the…

The objective of this study was to develop an online report writing activity that was a constructive and cooperative learning process for a course on traditional general physics experiments. Wiki, a CMC authoring tool, was used to construct the writing platform. Fifty-eight undergraduate students (33 men and 25 women), working in randomly assigned…

Mating between closely related individuals often causes reduced fitness, which is termed "inbreeding depression". Inbreeding is, therefore, a threat towards the persistence of animal and plant populations. Here we present methods and results from a practical for high-school and first-year university students and discuss learning outcomes…

Scientific freedom and openness are hallmarks of academia: relative to their counterparts in industry, academics maintain discretion over their research agenda and allow others to build on their discoveries. This paper examines the relationship between openness and freedom, building on recent models emphasizing that, from an economic perspective,…

On a partly sunny afternoon, a fourth-grade class at the Marietta Center for Advanced Academics in Marietta, Georgia, was gearing up to explore key concepts regarding the nature of light. Armed with translucent beads and white pipe cleaners, the classroom teacher asked each student to count eight beads and then encouraged them to closely observe…

The tendency of fluids to follow, in certain conditions, curved profiles is often referred to as the Coanda effect. A simple experiment modeling the common teapot effect, the curling of the liquid around the beak when it is poured, can be used in the classroom to illustrate simple dynamic principles and basic fluid dynamics concepts as well.

A clear view of the ocean may be used to measure the radius of the Earth. To an observer looking out at the ocean, the horizon will always form some angle [theta] with the local horizontal plane. As the observer's elevation "h" increases, so does the angle [theta]. From measurements of the elevation "h" and the angle [theta],…

Potassium dioxide, KO[subscript 2], (potassium superoxide) is an important compound owing to its ability to react with carbon dioxide to produce oxygen. This unique ability is employed to design rebreathing devices for submarines, space vehicles, and space suits. "Rebreathers" for firefighters and miners have also been designed using potassium…

What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called…

An electronic circuit for controlling "RLC" experiments is shown. This arrangement does not employ a function generator, which makes it more suitable when a wide range of "R," "L" and "C" values is required and a relatively high current is involved. This circuit can be used for driven and undriven DC…