This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

A lens based on liquid in the confined volume of a volumetric flask was presented as a potential projector to observe microscopic floating organisms or materials. In this experiment, a mosquito larva from a natural pond was selected as a demonstration sample. By shining a light beam from a laser pointer of any visible wavelength through the…

New undergraduate students arriving to study physics at the University of Bristol from 1975 onwards have all taken the same test of their knowledge and understanding of physics and mathematics. Many of the questions test knowledge of material that has been in the A-level syllabus for maths or physics throughout this period. The ability of incoming…

This article discusses an instructional strategy which explores eventual similarities and/or analogies between familiar problems and more sophisticated systems. In this context, the Atwood's machine problem is used to introduce students to more complex problems involving ropes and chains. The methodology proposed helps students to develop the…

In this paper we report on the use of two different light to frequency converters, four different light sources, three of which are novel and inexpensive, and a hand held digital multimeter with a frequency counter, suitable for making accurate and rapid determination of the optical inverse square law exponent of -2 to better than [plus or…

The use of a video camera may markedly improve demonstrations of optical spectra. First, the output electrical signal from the camera, which provides full information about a picture to be transmitted, can be used for observing the radiant power spectrum on the screen of a common oscilloscope. Second, increasing the magnification by the camera…

In this work, we studied the rolling motion of solid and hollow cylinders down an inclined plane at different angles. The motions were captured on video at 300 frames s[superscript -1], and the videos were analyzed frame by frame using video analysis software. Data from the real motion were compared with the theory of rolling down an inclined…

The "radioactive dice" experiment is a commonly used classroom analogue to model the decay of radioactive nuclei. However, the value of the half-life obtained from this experiment differs significantly from that calculated for real nuclei decaying exponentially with the same decay constant. This article attempts to explain the discrepancy and…

Across the world, freshwater is valued as the most critically important natural resource, as it is required to sustain the cycle of life. Evaporation is one of the primary environmental processes that can reduce the amount of quality water available for use in industrial, agricultural and household applications. The effect of evaporation becomes…

The basic theory of radio broadcasting is discussed from an experimental point of view. First, concepts like wave modulation and tuning are explained with the use of instruments in the physics laboratory. Then, a very basic radio receiver is described and assembled, whose most important feature, like in the old "crystal radios", is the absence of…

The purpose of this article is to describe the construction of a Sun clock and calendar (SCandC) that will allow an observer to not only see the time but also the symmetry properties of the Sun-Earth relative movement. A set of circles drawn on the SCandC will allow the observer to see their associated dates as well as to perform a visual…

What follows are several investigations involving string musical instruments developed for and used in a "Science of Sound & Light" course. The experiments make use of a guitar, orchestral string instruments and data collection and graphing software. They are designed to provide students with concrete examples of how mathematical formulae, when…

A simple experiment using low cost equipment for the determination of the density of granular materials, without immersing them in a liquid, is presented. It is based only on the ideal gas state equation, so it is a good experimental task for undergraduate and high school students. (Contains 2 tables and 5 figures.)

A pair of objects on an inclined plane are connected together by a string. The upper object is then connected to a fixed post via a spring. The situation is first analysed as a classroom exercise in using free-body diagrams to solve Newton's second law for a system of objects upon which many different kinds of force are acting (string tension,…

A simple model is developed that predicts the coefficient of rolling friction for an undriven laboratory cart on a track that is approximately independent of the mass loaded onto the cart and of the angle of inclination of the track. The model includes both deformation of the wheels/track and frictional torque at the axles/bearings. The concept of…