The requirement for a method of capturing problem solving on a whiteboard for later replay stems from my teaching load, which includes two classes of first-year university general physics, each with relatively large class sizes of approximately 80-100 students. Most university-level teachers value one-to-one interaction with the students and find…

The similar mathematical forms of Coulomb's law and Newton's law of gravitation suggest that two uniformly charged spheres should be able to orbit each other just as two uniform spheres of mass are known to do. In this paper we describe an experiment that we performed to demonstrate such an orbit. This is the first published account of a…

A pair of fine tweezers and a steady hand may well be enough to pick up a grain of sand, but what would you use to hold something hundreds of times smaller still, the size of only one micron? The answer is to use a device that is not mechanical in nature but that relies instead on the tiny forces that light exerts on small particles: "optical…

This paper is a brief summary of an "open-ended" physics experiment that gave my students a glimpse of what real physics research is like. They found it to be both fun and challenging. The subject of the experiment is the well-known Diet Coke and Mentos reaction. A more detailed description of the experimental results has been published elsewhere.

Doing physics "magic shows" for the general public or for local area schools is usually an integral part of any physics department's outreach program. These demonstration shows should not only teach fundamental physics principles with "standard" demonstrations (like the rocket cart) but should also include the "wow!" types of demonstrations for…

In this age of the microcomputer-based lab (MBL), students are quite accustomed to looking at graphs of position, velocity, and acceleration versus time. A number of textbooks argue convincingly that the slope of the velocity graph gives the acceleration, the area under the velocity graph yields the displacement, and the area under the…

Use of a microphone attached to a computer to capture musical sounds and software to display their waveforms and harmonic spectra has become somewhat commonplace. A recent article in "The Physics Teacher" aptly demonstrated the use of MacScope in just such a manner as a way to teach Fourier analysis. A logical continuation of this project is to…

The technology of podcasting, or creating audio or video files that can be subscribed to over the Internet, has grown in popularity over the past few years. Many educators have already begun realizing the potential of delivering such customized content, but most efforts have focused on lecture-style humanities courses or multimedia arts courses.…

In the past few decades, the physics teaching community has witnessed a surge in creative and often effective ways of using technology to improve physics instruction. Most of these findings suggest how technology can help instructors create interactive learning environments and how interactivity influences the effectiveness of physics learning.…

Like many high school and college physics teachers, I have found playing vector games to be a useful way of illustrating the concepts of inertia, velocity, and acceleration. Like many, I have also had difficulty in trying to get students to understand Newton's law of universal gravitation, specifically the inverse-square law and its application to…

I recently had a cardiac stress test. It was my fourth. Its purpose was to determine whether my heart is pumping an adequate quantity of blood during exercise. Additionally, is there a partial arterial blockage or damaged heart muscle? The test involves the patient receiving an injection of Cardiolite[R], a substance containing a molecule to which…

We describe a model of the human eye that incorporates a variable converging lens. The model can be easily constructed by students with low-cost materials. It shows in a comprehensible way the functionality of the eye's optical system. Images of near and far objects can be focused. Also, the defects of near and farsighted eyes can be demonstrated.

The electrical design of the common hair dryer is based almost entirely on relatively simple principles learned in introductory physics classes. Just as biology students dissect a frog to see the principles of anatomy in action, physics students can "dissect" a hair dryer to see how principles of electricity are used in a real system. They can…

This paper describes a course aimed at developing understanding of measurement and uncertainty in the introductory physics laboratory. The course materials, in the form of a student workbook, are based on the probabilistic framework for measurement as recommended by the International Organization for Standardization in their publication "Guide to…

Fruit batteries and saltwater batteries are excellent ways to explore simple circuits in the classroom. These are examples of air batteries in which metal reacts with oxygen in the air in order to generate free electrons, which flow through an external circuit and do work. Students are typically told that the salt or fruit water acts as an…