Carl Mungan, United States Naval Academy
mungan@usna.edu

A wonderful comparison of pinhole images of the sun projected onto a wall by openings in a tree before and during a partial solar eclipse can be found on page 259 of the May 2016 issue of The Physics Teacher. Another lovely photograph in the same issue is of a chain fountain on page 320. David Keeports presents some optics-based tricks to correct near- or far-sightedness without glasses on page 375 of the September 2016 issue.

In the June 2016 issue of the American Journal of Physics John Lekner works out the charge ratio as a function of distance of separation of two like-charged (but different radius) metal spheres that will cause them to attract (rather than repel) due to their mutual polarization. An article of page 413 of the same issue makes the provocative claim that many counterclockwise thermodynamic cycles are not refrigerators. A paper by Robert Hilborn in the July 2016 issue shows that glib statements in an introductory course about electromagnetic field energy being the mechanism for exchange between charges are seldom helpful and often flat out wrong; it is preferable to stick instead to the potential energy of the configuration. A systematic approach to the problem of determining the general shapes of noncircular wheels rolling smoothly on nonflat roads is presented on page 581 of the August 2016 issue.

Article 045002 in the July 2016 issue of the European Journal of Physics hypothesizes that the reason a cat can survive falls from small or large heights but not from intermediate values (corresponding to about the seventh floor of a building) is because the jerk has a maximum for a descent of 20 m, causing a cat to stiffen with fear. In the May 2016 issue of Physics Education, de Carvalho considers some contradictions in the force and torque balance of a two-pan scale. In the July 2016 issue, Marciotto calls for an improved derivation of Bernoulli’s principle in the introductory course. Both journals can be accessed at the IOP Science Journals webpage.

Page 429 of the May 2016 issue of Resonance has an article discussing some errors in the Feynman Lectures on Physics about crystal symmetries. Page 447 of the same issue considers the paradox that, due to the shell theorem, there would be no gravitational force in an infinite homogenous universe. Finally page 453 shows that a cube of heavy ice would sink in ordinary water, unlike what a cube of ordinary ice does; dying the cubes with food coloring makes for a nifty demo. A special issue in the June 2016 issue on Hamilton reviews his work on optical wavefronts on page 511 and on quaternions on page 529. These articles can be freely accessed on the May 2016 issue.

An article on page 1289 of the July 2016 issue of the Journal of Chemical Education discusses a detailed lab to investigate the bandgap, doping, and structure of light-emitting diodes. Pages 1340 to 1352 of the August 2016 issue has a great set of science book reviews by four different readers, including “What Every Science Student Should Know” and “Seven Brief Lessons on Physics.” Pages 1441 to 1451 of the same issue describes two (admittedly lengthy) experiments to prepare and characterize nanoparticle-based materials. Finally the September 2016 issue has an article on page 1578 applying the variational method to calculating bonding and antibonding orbitals of hydrogen molecules starting from Gaussian trial wavefunctions. The journal archives are on the Journal of Chemical Education archives page.

Article 010135 in Physical Review Physics Education Research compares three different approaches to teaching wave optics to introductory students: by sketching sinusoidal waves, via snapshots of the electric field at various instants, or by using phasors.

Disclaimer – The articles and opinion pieces found in this issue of the APS Forum on Education Newsletter are not peer refereed and represent solely the views of the authors and not necessarily the views of the APS.