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…

iSchlenk, a portable instructional cart with equipment for hands-on student experience in safe handling of air-sensitive, moisture-sensitive, toxic, pyrophoric, and/or radioactive chemical materials, is described. The cart, for use by =4 students, has compressed air and vacuum from a diaphragm vacuum pump supplied to 4 three-port Schlenk lines…

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…

The aim of this paper is to introduce a simple and low-cost experimental setup that can be used to study the eddy current brake, which considers the motion of a sliding magnet on an inclined conducting plane in terms of basic physical principles. We present a set of quantitative experiments performed to study the influence of the geometrical and…

Discusses the use of a modified electron spin resonance apparatus to demonstrate some features of the expression for the transition probability per second between two energy levels. Applications to the third year laboratory program are suggested. (CC)

Introduces a method for two-dimensional kinematics measurements by hanging marbles with long strings. Describes experimental procedures for conservation of momentum and obtaining the coefficient of restitution. Provides diagrams and mathematical expressions for the activities. (YP)

Information related to the history of optics with emphasis on the classical and medieval periods is presented. Notes are included on experiments dealing with refraction at a plane interface between two media; refraction by transparent spheres; light, color, and reflection by transparent spheres. (Author/SA)

The life and work of Isaac Newton and his investigations of light and color are described in detail. Notes include preliminary observations of chromatic dispersion; dispersion by an equilateral prism; the "Experimentum Crucos" or the composite nature of white light; the nature of colored light and illumination; transmissions and…

Presented is information related to the life and work of Charles Coulomb as well as detailed notes of his measurements of the distribution of electricity on conductors. The two methods that he used (the large torsion balance, and the timing of "force" oscillations) are described. (SA)

Introduces three laboratory exercises which develop an understanding of principles of mechanics by using examples of bicycle operation: Newton's laws, statics and dynamics, and energy relationships. Describes related theory and laboratory procedures with diagrams and pictures in each exercise. (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)

Presents a device to illustrate the concepts of entropy of mixing and the contribution of one term in the Gibb's equation. Notes the device is relatively easy to construct and provides a visual demonstration on diffusion. (MVL)