Dedicated to the strengthening of the teaching of introductory physics at all levels, The Physics Teacher provides peer-reviewed materials to be used in the classrooms and instructional laboratories. It includes:
Innovative physics demonstrations; New ways of doing lab experiments; Ideas for presenting difficult concepts more clearly; Suggestions for implementing newer technology into teaching; Historical insights that can enrich the physics course and Book and film reviews.
Special features include Physics Challenge Solutions, Fermi Questions, and Figuring Physics.
Variations of a demonstration in which a sheet of paper or a bead is levitated in a grazing stream as from one's breath have been published in several sources.1–4 Even a massive ball can be deflected into the robust flow from a leaf blower.5 The attraction is surprising because it is often quite stable and seems to conflict with the familiar transient repulsion felt from a stream's impact.
Recent and exciting discoveries in astronomy and cosmology have inspired many high school students to learn about these fields. A particularly fascinating consequence of general relativity at the forefront of modern cosmology research is gravitational lensing, the bending of light rays that pass near massive objects. Gravitational lensing enables high-precision mapping of dark matter distributions in galaxies and galaxy clusters, provides insight into large-scale cosmic structure of the universe, aids in the search for exo-planets, and may offer valuable insight toward understanding the evolution of dark energy. In this article we describe a gravitational lensing lab and associated lecture/discussion material that was highly successful, according to student feedback. The gravitational lens unit was developed as part of a two-week summer enrichment class for junior and senior high school students. With minor modifications, this lab can be used within a traditional classroom looking to incorporate topics of modern physics (such as in a unit on optics).
This activity is designed to illustrate an application of resistive forces in the introductory physics curriculum with an interdisciplinary twist. Students are asked to examine images of riverbed boulders after a flood and estimate the water flow that was needed to push the boulders downstream. The activity provides an opportunity for students to gain an understanding of the physics of natural phenomena with applications to environmental science and environmental engineering, to gain a stronger appreciation for physical modeling and estimation, and to become environmental detectives!
It is a common practice to fix a vertical gnomon and study the moving shadow cast by it. This shows our local solar time and gives us a hint regarding the season in which we perform the observation. The moving shadow can also tell us our latitude with high precision. In this paper we propose to exchange the roles and while keeping the shadows fixed on the ground we will move the gnomon. This lets us understand in a simple way the relevance of the tropical lines of latitude and the behavior of shadows in different locations. We then put these ideas into practice using sticks and threads during a solstice on two sites located on opposite sides of the Tropic of Capricorn.
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NASA's Kepler Mission (Fig. 1) has been wildly successful in discovering exoplanets. This paper summarizes the mission goals, briefly explains the transit method of finding exoplanets and design of the mission, provides some key findings, and describes useful education materials available at the Kepler website.