Collective motion in living matter is highly intriguing but can also be observed in charged colloidal systems. Collective motion observed in colloidal systems requires extensive material synthesis, external stimuli, and advanced characterization methods that might be highly costly to be employed for teaching. Besides that, colloidal systems can…

Resonance is a widely observed physical phenomenon, occurring when an oscillator experiences a driving force whose frequency closely matches one of its own natural frequencies. Due to its broad applicability in physics, resonance is a familiar topic in the physics teaching literature. Previous studies include resonant energy transfer between…

In everyday language, "zero" and "nothing" are generally synonyms if not interchangeable. In physics, however, these two terms are quite distinct. Zero often refers to a number and nothing often refers to the vacuum state. Furthermore, the number zero has a variety of different meanings, among which physics teachers shift…

In this work, different alternatives for locating the optimal feed stage in a distillation column as well as the effect of the feed temperature are studied, by solving a classroom problem. The results obtained permit us to select the best way to optimize the feed stage location as well as to detect what thermal feed phase conditions should be…

What does it mean to "make sense" of physics? It's not a simple question. Most people have an intuitive feeling for when things do (or do not) make sense to them. But putting this feeling into words--especially actionable words--is another task entirely. Generally speaking, there are two ways in which we commonly use the term "make…

A simple method is described for measuring liquid density based on stretching of the spring and equilibrium of weight and elastic force. The method involves placing a container with liquid under test on the spring causing a stretch of the spring that is directly proportional to the weight of the liquid. With this technique, the liquid density can…

Proteopedia (proteopedia.org) is an open resource to explore the structure--function relationship of proteins and other biomolecules. This guide provides practical advice on how to incorporate Proteopedia into teaching the structure and function of proteins and other biomolecules. For 11 activities, we discuss desired outcomes, setting…

The concept of redshift is very often used in teaching physics and astronomy, as well as in science public outreach. Redshift is an interesting topic, used to describe many physical processes such as the Doppler effect or the expansion of the universe. Nevertheless, there are unfortunately also misconceptions about redshift. When facing the…

In this experiment, students explore the synthesis and physical property characterization of the magnetic material strontium hexaferrite (SrFe[subscript 12]O[subscript 19]). SrFe[subscript 12]O[subscript 19] crystallites are prepared by a simple but fascinating sol-gel autocombustion synthesis. The prepared powder is compacted into pellets and…

Races between moving objects are an engaging way to teach dynamics to introductory physics students. One standard example consists in racing hollow and solid cylinders as they roll down an inclined plane. Another striking demonstration is a race between two marbles on side-by-side tracks that start and end together, but with one track taking a…

The falling temperature of the photosphere with height is responsible for the effect known as limb darkening. The Sun is not equally bright all over the disc. When we observe the Sun towards the limbs, it appears to get darker. Light from the photosphere travels through an absorptive medium. Therefore, one can see only so far into the photosphere.…

Einstein's special theory of relativity includes many non-intuitive and apparently paradoxical conclusions about space and time. One of these is time dilation, the fact that a clock moving relative to an observer runs slower than an identical clock at rest in the observer's reference frame. This is clearly exhibited in the extended mean lifetime…

The recent discovery of preserved cells and soft tissues in certain dinosaur bones seems incompatible with an age of millions of years, given the expectation that cells and soft tissues should have decayed away after millions of years. However, evidence from radiometric dating shows that dinosaur fossils are indeed millions of years old. Under…

Chemical scientists and engineers are interested in controlling chemical processes to attain specific goals, from synthesizing a desired substance to hindering a particular transformation. Nevertheless, students typically have few opportunities to develop the understandings and practices that are required to effectively engage in chemical control.…

This study proposes a lab experiment consisting of three consecutive steps designed to expose undergraduate students to the fundamental aspects of nanoscience. Two different procedures for the reduction of silver ions were provided: Th was obtained. Next, the students explored the aggregation process of silver nanoparticles by converting one…