Graphing predictions is especially important in classes where relationships between variables need to be explored and derived. In this article, the author describes how his students sketch the graphs of their predictions before they begin their investigations on two laboratory activities: Distance Versus Time Cart Race Lab and Resistance; and…

An attempt to model the physical process of annealing lead to the development of a type of combinatorial optimization algorithm that takes on the problem of getting trapped in a local minimum. The author presents a Microsoft Excel spreadsheet that illustrates how this works.

Since electrical field concepts are usually unfamiliar, abstract, and difficult to visualize, conceptual analogies from familiar gravitational phenomena are valuable for teaching. Such analogies emphasize the underlying continuity of field concepts in physics and support the spiral development of student understanding. We find the following four…

In the 1930s physicists were confronted by two conflicting values for the charge of the electron as measured with great precision by two different methods. Could it be that there are two kinds of (negative) electrons, differing in charge by a fraction of a percent? The experiments were reconciled when a small systematic error in one of the…

Once an intriguing topological novelty known only to mathematicians, the Mobius strip has become a source of fascination and inspiration to the layperson and artist alike. Principal among its features are the two strange properties that the Mobius strip is a surface with only one side and one edge. A Mobius strip is readily formed by taking a long…

When opening a thermos flask filled with coffee, one often "hears" the equalization of the pressure difference that appears to be present between the air cavity inside the flask and the surrounding room atmosphere. Recently we discussed this phenomenon while drinking coffee and guessed about the direction of the gas stream accompanying the…

We observed, using polarized light microscopy, the supercooling of the blue phase (BPI) of cholesteryl proprionate and measured the corresponding liquid crystalline phase transition temperatures. From these temperatures and additional published data we have provided, for the benefit of undergraduate physics students, a nontraditional example…

The Enskog factor [chi] plays a central role in the theory of dense gases, quantifying how the finite size of molecules causes many physical quantities, such as the equation of state, the mean free path, and the diffusion coefficient, to deviate from those of an ideal gas. We suggest an intuitive but rigorous derivation of this fact by showing how…

Thought Field Therapy (TFT) is a novel therapy that employs finger tapping on purported acupressure points. Over the past decade, TFT, promoted on the Internet and through testimonials of fast cures, has gained popularity with therapists, including clinical social workers. Although TFT claims to cure a wide variety of psychological and physical…

The construction of a fluorometer and a spectrofluorometer using flashlight or a sunlight excitation source in a shoebox and the eye as a detector is being described. The assembly helps in understanding several fundamental ideas related to the subject very easily.

An approach is presented that starts from two fundamental concepts in organic chemistry, chirality and aromaticity, and combines them into a simple rule for stating selection rules for pericyclic reactions in terms of achiral Huckel-aromatic and chiral Mobius-aromatic transition states. This is illustrated using an example that leads to apparent…

Most of the articles and textbooks that show drawings of enantiomorphous crystals use an inadequate view to appreciate the fact that they are non-superimposable mirror images of one another. If a graphical presentation of crystal chirality is not evident, the main attribute of crystal enantiomorphism can not be recognized by students. The classic…

Numerous connections exist between climate science and topics normally covered in physics and physical science courses. For instance, lessons on heat and light can be used to introduce basic climate science, and the study of electric circuits provides a context for studying the relationship between electricity consumption and carbon pollution. To…

Examples of plastic solar-cell technology to illustrate core concepts in chemistry are presented. The principles of operations of a plastic solar cell could be used to introduce key concepts, which are fundamentally important to understand photosynthesis and the basic process that govern most novel optoelectronic devices.

This paper aims to supplement the scant literature on the history of ideas about the nature of sound. It presents how notions about the production and propagation of sound developed from antiquity up to the 17th century, i.e. from the time of Pythagoras to the time of Sauveur. It will highlight and examine the principles of sound that were…