Crystals are beautiful structures--yet they occur naturally in dirty and remote places. In the inquiry-based activity described here, students will enjoy the process of creating their own crystals and using microscopes to examine them. It demonstrates the process of mineral concentration and deposition. Upon completing this activity, students…

The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, "The Kaye effect", as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid…

A problem-based approach to the teaching of mechanical wave propagation, focused on observation and measurement of wave properties in solids and on modelling of these properties, is presented. In particular, some experimental results, originally aimed at measuring the propagation speed of sound waves in metallic rods, are used in order to deepen…

Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a…

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…

A phase-shift interferometry experiment is proposed, working on a Twyman-Green optical configuration with additional polarization components. A guideline is provided to modern phase-shift interferometry, using concepts and laboratory equipment at the level of undergraduate optics courses. (Contains 5 figures.)

Volume phase holographic (VPH) optical elements have made a major contribution to Raman spectroscopy by providing notch filters, and VPH gratings that provide remarkable performance advantages over previous technologies. Holographic notch filters have eliminated Rayleigh scattered laser light from single monochromators, thereby contributing to the…

The angular speed of a spinning object is commonly measured using a stroboscope or a mechanically or optically coupled tachometer. We present here an alternate, simple, and instructive method to measure it using a microphone and a computer.

An important aspect of teaching biology is to expose students to the concept of biodiversity. For this purpose, bacteria are excellent examples. The advanced placement (AP) biology class at Cedar Shoals High School in Athens, Georgia, learned how to explore bacterial biodiversity using molecular fingerprinting. They collected marine water samples,…

Sampling experiments utilizing field portable instruments are instructional since students collect data following regulatory protocols, evaluate it, and begin to recognize their civic responsibilities upon collecting useful data. A lead-in-soil experiment educated students on a prevalent exposure pathway. The experimental site was a pre-1950…

A computer-interfaced drop counter is described that serves as an inexpensive alternative to a fraction collector for column chromatography experiments. Undergraduate biochemistry laboratories frequently do not have the budget to purchase fraction collectors. Protocols that call for the manual measurement of fraction volumes as well as the manual…

In this paper, we present a multi-dimensional study concerning Heisenberg's "gamma ray microscope", a thought experiment, which is intimately connected with the historical development of quantum mechanics (QM), and also with the most disputed interpretations of quantum theory. In this study: (a) we investigate how philosophers of science read and…

The paper describes a teaching model of the atomic force microscope (AFM), which proved to be successful in the role of an introduction to nanoscience in high school. The model can demonstrate the two modes of operation of the AFM (contact mode and oscillating mode) as well as some basic principles that limit the resolution of the method. It can…

The properties of the arrival time distribution of particles in a detector have been studied by the use of a small Geiger counter, with a GPS device to tag the event time. The experiment is intended to check the basic properties of the random arrival time distribution between successive events and to simulate the investigations carried out by…

We present a pedagogic approach aimed at modelling electric conduction in semiconductors in order to describe and explain some macroscopic properties, such as the characteristic behaviour of resistance as a function of temperature. A simple model of the band structure is adopted for the generation of electron-hole pairs as well as for the carrier…