In the class of 2013, a record number of students earned bachelor's degrees in physics: 7,363. This is more than double the number of students doing so only 14 years earlier. Over the same time period, the total number of bachelor's degrees awarded in all disciplines was up also, but only by about 40%. The graph shows the number of…

Universities and even high schools are moving more and more to online instruction as a cost-effective way to reach more students with fewer resources. This naturally raises the question: Can online learning be effective? (The question is not "Is online learning effective?" because just like face-to-face instruction, online instruction…

Finding topics that inspire students is an important aspect of any physics course. Virtually everyone is fascinated by "Tyrannosaurus rex," and the excitement of the class is palpable when we explore scaling effects in "T. rex" and other bipedal theropod dinosaurs as part of our discussion of mechanics and elasticity. In this…

Although we experience motion simply as displacement, we study it through complicated concepts such as acceleration, force, and mass, departing from our everyday experience. But it looks like we can stay attached to our primordial notions of time and length without appealing to any other concepts and still have interesting results.

In a usual modern physics class the Compton effect is used as the pedagogical model for introducing relativity into quantum effects. The shift in photon wavelengths is usually introduced and derived using special relativity. Indeed, this works well for explaining the effect. However, in the senior author's class one of the student coauthors…

I had a solid geometry teacher in high school who, when looking at a particular theorem, liked to say, "It's intuitively obvious." In college I heard that same phrase from a professor teaching electrodynamics. And when I taught in college a colleague of mine liked to tell his students that the laws of physics were "intuitively…

It has often been reported in this column that smartphones are very suitable tools for exploring the physical properties of everyday phenomena. A very good example of this is an elevator ride. In addition to the acceleration processes, oscillations of the cabin are interesting. The present work responds to the second aspect.

Humans have evolved to follow their intuition, but as any high school physics teacher knows, relying on intuition often leads students to predict outcomes that are at odds with evidence. Over the years, we have attempted to make this intuition-outcome disparity a central theme running throughout our physics classes, with limited success. Part of…

In 1879, in the midst of the debate between English and continental scientists about the nature of cathode rays, William Crookes conducted an experiment in which a small mill or "paddle wheel" was pushed along tracks inside a cathode ray tube (CRT) (similar to that shown in Fig. 1) when connected to a high-voltage induction coil. Crookes…

We cannot hope for a new generation of scientists and engineers if we don't let our young students take ownership of their scientific and engineering explorations, if we don't let them enjoy the hands-on cycle of design and production, and if we don't let them implant their creativity into a technologically friendly environment.…

Since 1987, the Statistical Research Center at the American Institute of Physics has regularly conducted a nationwide survey of high school physics teachers to take a closer look at physics in U.S. high schools. We contact all of the teachers who teach at least one physics course at a nationally representative sample of all U.S. high schools-both…

A Genecon is an inexpensive hand-cranked dc electric generator. You can use it to charge a one-farad supercapacitor. If you stop cranking the handle, the capacitor will discharge, sending a current into the Genecon and thereby causing the handle to start turning as an electric motor. How does the current direction compare before and after you stop…

A vehicle starts from rest at constant acceleration, then cruises at constant speed for a time. Next, it decelerates at a constant rate.… This and similar statements are common in elementary physics courses. Students are asked to graph the motion of the vehicle or find the velocity, acceleration, and distance traveled by the vehicle from a given…

In undergraduate E&M courses the magnetic field due to a finite length, current-carrying wire can be calculated using the Biot-Savart law. However, to the author's knowledge, no textbook presents the calculation of this field using the Ampere-Maxwell law: ?B [multiplied by] dl = µ[subscript 0] (I + e[subscript 0] dF/dt) [multiplied by] 1

Today, almost all introductory physics textbooks include standardized "rules" on how to find the number of significant figures in a calculated value. And yet, 30 years ago these rules were almost nonexistent. Why have we increased the role of significant figures in introductory classes, and should we continue this trend? A look back at…