To a student in introductory physics, using vectors is at best an exercise in bookkeeping. A two-dimensional kinematics problem effectively doubles the number of equations that a student must know, and invites the student to memorize factoids: "The horizontal motion is constant," "Gravity is only in the y-direction," etc. Force…

X-rays are such an important and familiar part of the electromagnetic spectrum, but is there a way to safely bring x-rays into your lecture? The demo team at the University of California at Berkeley seems to have managed this. They have an x-ray safe box that they use to produce a live x-ray image on a fluorescent screen. In this article, we…

Collisions are real-world situations from everyday life (such as car crashes, playing billiards, etc.) that can be described and understood by the principle of conservation of momentum. One might expect that learning from simple collisions might help students understand more complicated physical phenomena. However, from our teaching experiences we…

Energy is an important crosscutting concept in all science disciplines, and energy conservation is widely regarded as one of the most important principles in physics. Over the years, numerous graphical representations have been proposed that allow learners of physics to visualize energy states and dynamics in a particular situation. Each diagram…

Power Boxes are a new representation to provide students with a conceptual resource to analyze direct current (DC) circuits and to build conceptual understanding of energy and power use in circuits. Power Boxes are designed to provide an intermediate, conceptual step between drawing a circuit diagram and solving calculations. In this paper, we…

For many students, introductory physics is an enormous hurdle to cross in their educational careers. Studies show that many students struggle with basic vector concepts and hold misconceptions of fundamental principles like Newton's laws, ideas essential to the understanding of higher-order physics concepts and for achieving success in engineering…

The observation that the shadows of objects change during the course of the day and also for a fixed time during a year led curious minds to realize that the Sun could be used as a timekeeper. However, the daily motion of the Sun has some subtleties, for example, with regards to the precise time at which it crosses the meridian near noon. When the…

This paper describes a pictorial approach to Lenz's law that involves following four steps and drawing three pictures to determine the direction of the current induced by a changing magnetic flux. Lenz's law accompanies Faraday's law, stating that, for a closed conducting loop, the induced emf (electromotive force) created by a changing magnetic…

As physics instructors, we try to help our students learn physics. But most of us begin to realize that our students are not learning as much as we hope they would. As we listen to our students, we begin to see some of their difficulties. Some of their difficulties are expected, but some are unexpected. One such difficulty is drawing the force…

A ternary diagram is a graphical representation used for systems with three components. They are familiar to mineralogists (who typically use them to categorize varieties of solid solution minerals such as feldspar) but are not yet widely used in the physics community. Last year the lead author began using ternary diagrams in his introductory…

Energy is a crosscutting concept in science and features prominently in national science education documents. In the "Next Generation Science Standards," the primary conceptual learning goal is for learners to conserve energy as they "track" the transfers and transformations of energy within, into, or out of the system of…

In many states, electric fences are used to prevent animals from leaving a designated area, for example for grazing. They are quite well known by most students and can therefore serve as daily-life examples of electric circuits. Besides helping to grasp the ideas of Kirchhoff's laws for voltages and currents in circuits according to loop and…

Multiple representations are a valuable tool to help students learn and understand physics concepts. Furthermore, representations help students learn how to think and act like real scientists. These representations include: pictures, free-body diagrams, energy bar charts, electrical circuits, and, more recently, computer simulations and…

Books, cartoons, movies, and video games provide engaging opportunities to get both science and nonscience students excited about physics. An easy way to use these media in one's classroom is to have students view clips and identify unusual events, odd physics, or list things that violate our understanding of the physics that governs our universe.…

Proposes an alternative approach to locating the image formed by a lens. Two special rays are used to locate the image, then a number of other rays are drawn in to indicate that light from the object passes through every part of the lens. (MVL)