The article presents simple outdoor experiments for measuring illuminance on inclined surfaces with a luxmeter. A hill model is used to investigate the difference in illuminance between a sunny side and a shady side of a hill, with up to a fivefold difference found between the two sides on a sunny day. The illuminance of the sunny side of the hill…

In this paper we present a system aimed at demonstrating the photoacoustic (PA) effect for educational purposes. PA imaging is a hybrid imaging modality that requires no contrast agent and has a great potential for spine and brain lesion characterisation, breast cancer and blood flow monitoring notably in the context of fetal surgery. It relies on…

We describe the design of a simple homemade apparatus for the measurement of the refractive indices of liquids and demonstration of refraction. A circular transparent plastic tank and a lazy Susan are held concentrically. A laser pointer is mounted on the lazy Susan with its laser beam pointing radially through the centre of the plastic tank.…

Light is radiation in wavelengths composed of many colors that are visible to the eyes. These wavelengths can be separated. One way to separate colors is with a filter. Filters keep certain wavelengths out and allow other wavelengths to pass through. In this article, the authors discuss an activity to provide students the opportunity to build a…

Describes the computer generation of random and regular arrays of apertures on photographic film and their applications for classroom demonstrations of the Fraunhofer patterns produced by simple and complex apertures, Babinet's principle, resolution according to the Rayleigh criterion, and many other aspects of diffraction. (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 Herschel's demonstration of interference arising from many coherent rays. Presents a method for students to reproduce this demonstration and obtain beautiful multiple-beam interference patterns. (CCM)

Describes how to produce a rainbow in the classroom using a laser and a large sphere, or a partial rainbow using a cylinder of water and a light source. (BR)

Describes an apparatus designed to investigate molecular motion by means of light scattering. Light from a He-Ne laser is focused into a cell containing a suspension of polystyrene spheres. The scattered light, collected on the photosurface of a photomultiplier tube, is analyzed. The apparatus won first prize in Demonstration Lecture Apparatus in…

Describes activities concerning interference phenomena derived from illuminated rotating soap films. Suggests reflecting incident light off of the soap film onto a projection screen. Discusses several possible experiments, how to make soap solutions, and vibrating soap films. (MVL)