This article describes a combined UV-photometer and fluorimeter constructed from 3 LEDs and a few wires, all held in place with Lego bricks. The instrument has a flexible design. In its simplest version, two UV-LEDs (355 nm) are used as light source and to detect absorption, and a third LED, in the visible spectrum (e.g., 525 nm), is used to…

The magic flask, which is a kind of black box activity, builds an environment for science teachers to discuss nature of science in a formal or/and informal learning environment in the context of the history of science through an explicit-reflective approach. In the activity, the nature of science (NOS) aspects are explicitly addressed and…

Understanding how scientific conclusions are drawn from data is central to learning about the nature of science. Many students struggle with aspects of reasoning from data, including identifying relationships among variables, interpreting graphs, coordinating theory and evidence, and not allowing personal beliefs to outweigh the data when forming…

In most secondary physics textbooks, waves are first introduced with examples of mechanical waves because they can be illustrated by drawings and photographs. However, these illustrations are static and cannot reflect the dynamic nature of waves. Although many mechanical waves (e.g. water waves and vibrating strings) can be easily shown using…

Chemical kinetic experiments to determine rate laws are common in high school and college chemistry courses. For reactions involving a color change, rate laws can be determined experimentally using spectrophotometric or colorimetric equipment though this equipment can be cost prohibitive. Previous work demonstrated that inexpensive handheld camera…

This longitudinal study reports the results of a replication of "Tutorials in Introductory Physics" in high schools of a Latin-American country. The main objective of this study was to examine the suitability of "Tutorials" for local science education reform. Conceptual learning of simple resistive electric circuits was…

Discusses laser demonstration for invoking interest in science, especially physics. Describes some examples, such as diffraction, scattering, expansion by diverging lens, internal reflection in a light pipe, and illumination through optical cable. Provides some practical hints for the demonstration. (YP)

Discusses the making of a light engine powered by sunlight or a lamp. Describes the materials and construction method with detailed specifications and diagrams. (YP)