A student laboratory experiment to investigate the intrinsic and extrinsic bandgaps, dopant materials, and diode design in light-emitting diodes (LEDs) is presented. The LED intrinsic bandgap is determined by passing a small constant current through the diode and recording the junction voltage variation with temperature. A second visible…

Laboratory activity is closely related and yet is essential in the process of science teaching-learning. The hands-on laboratory experiment is the one normally used in school. Particularly with the state of online schooling, it is quite challenging to perform a hands-on laboratory activity. The combination of inquiry-based learning with virtual…

In recent years, nanomaterials have entered our daily lives via consumer products; thus, it has become increasingly important to implement activities to introduce these novel materials into chemistry curricula. Here we introduce a newly developed fluorescent nanomaterial, carbon dots, as a more environmentally friendly alternative to heavy-metal…

GEANT4 simulations of the processes affecting the transport and collection of optical photons generated inside a scintillation detector were carried out, with the aim to complement the educational material offered by textbooks to third-year physics undergraduates. Two typical situations were considered: a long scintillator strip with and without a…

When illuminating four "mystery" vials of nanoparticle solution with a 405-nm light emitting diode (LED), four distinct colors related to the peak wavelength of fluorescent emission can be observed. This phenomenon perplexes high school physics students and leads to the subsequent exploratory question, "Why are the four vials emitting a different…

To promote understanding of the authority of the primary literature in students taking our biochemistry laboratory courses, a biochemistry laboratory exercise on the determination of an acceptable molar absorptivity value of 2-nitrophenol (2-NP) was developed. This made the laboratory course much more relevant by linking to a thematic thread,…

A pair of fine tweezers and a steady hand may well be enough to pick up a grain of sand, but what would you use to hold something hundreds of times smaller still, the size of only one micron? The answer is to use a device that is not mechanical in nature but that relies instead on the tiny forces that light exerts on small particles: "optical…

Describes an experiment that allows the students to verify the assumption that light travels in straight lines. (GS)

The diffraction of a full thermal atomic potassium beam by a single slit was observed. Four experimental diffraction patterns were compared with that predicted by de Brogtie's hypothesis and simple scalar Fresnel diffraction theory. Possible reasons for the differences were discussed. (LC)

Describes a series of simple and nontraditional experiments that enable students to discover the properties of infrared radiation by studying the propagation, reflection, diffusion, and refraction of infrared. The experiments rely on two modules, an infrared transmitter and an infrared receiver. (SAH)

Describes the use of laboratory equipment to demonstrate (1) the interference of light coming from an air wedge, (2) the generation of gas-filled soap bubbles, and (3) the generation of beats with a ripple tank. (LC)

Describes an experiment that introduces students to the different types of UV rays and their effects on living things by using appropriate teaching materials and equipment. Demonstrates the effects of exposure to UV-B (fluorescent) and UV-C (germicidal) lamps by using bananas, duckweed, and the fruit fly. (Contains 14 references.) (Author/YDS)