Develops a simple core-halo model of a galaxy that exhibits the main features of observed rotation curves and quantitatively illustrates the need to postulate halos of dark matter. Uses only elementary mechanics. (Author/MVL)

Describes a hands-on activity in which the student's task is to design testing procedures and use appropriate formulas to meet the objectives of a two-dimensional projectile motion lab. (ZWH)

Describes a method for demonstrating beat phenomena by creating standing waves in strings. (WRM)

Describes a laboratory activity in which students speculate about the extent to which Galileo actually performed an experiment to determine that all pendulums of a given length have the same period, independent of amplitude. (WRM)

Discusses the events surrounding a famous picture of Albert Einstein in which he poses near a blackboard containing a tensor form of his 10 field equations for pure gravity with a question mark after it. Speculates as to the content of Einstein's lecture and the questions he might have had about the equation. (Contains over 30 references.) (WRM)

The subject of biomechanics is growing as athletes turn to science to improve their performance, and biomechanics interests many students and is a good area in which to investigate forces and Newton's laws. Uses force platforms to quantify such studies. (Author/ASK)

While it is most often the case that an understanding of physics can simplify mathematical calculations, occasionally mathematical precision leads directly to a better physical understanding of a situation. Presents an example of a mechanics problem in which careful mathematical derivation can lead directly to a deeper physical understanding of…

Explains why one orientation of an asymmetric spring-and-mass system leads to a higher frequency of 0000000000 than another orientation. (WRM)

Explains the shape distortions that take place in fluid packets (bubbles or drops) with steady flow motion by using the laws of Archimedes, Pascal, and Bernoulli rather than advanced vector calculus. (WRM)

Describes nine basic experiments that demonstrate the wave nature of light and the optical properties of water. Finds that a laser pointer works well as a light source in the laboratory. (CCM)

Discusses the nature and orientation of the forces that allow an engineless airplane (a glider or sailplane) to fly. A glider flying at constant velocity provides a nice example of an object moving under the action of several forces that add to zero. (WRM)

Explains how "Downy Ball" fabric softener dispensers can be used to demonstrate Newton's First Law in physics class. (WRM)

Argues that it is advantageous to adopt a more modern approach that systematically builds on students' knowledge of the atomic structure of matter and elementary mechanics. (Author/CCM)

Force in modern classical mechanics is unique, both in terms of its logical character and the conceptual difficulties it causes. Force is well defined by a set of axioms that not only structures mechanics but science in general. Force is also the dominant theme in the "misconceptions" literature and many philosophers and physicists alike have…

A method of measuring the orbital velocity of the Moon around the Earth using a digital camera is described. Separate images of the Moon and stars taken 24 hours apart were loaded into Microsoft PowerPoint and the centre of the Moon marked on each image. Four stars common to both images were connected together to form a "home-made" constellation.…