Discusses the puzzling effects of shadows cast in water. Demonstrates the effects of various objects and surface curvatures on the behavior of light rays transmitted through water. (CW)

Discusses the optics of fly fishing, considering where to cast the fly once a fish is seen. Also considers what the fisherman looks like to the fish, examining refraction at a water surface, actual and apparent light rays, and how sticks in the water might look to a fish. (JN)

A retroreflector is a mirror that removes distortion from a light beam. Describes experiments using the retroreflector as well as related phenomena. (JN)

Explains the color change of the sky by using scattering with science history. Provides several diagrams in each case, such as daylight, twilight, just after sunset, setting sun, and earth's shadow. Presents a reference of three further reading materials. (YP)

What shade of gray a surface appears is related to the perceived distribution of light and shadow, which in turn depends on the perceived spatial relation between the surface and its neighbors. (Author/ BB)

Discusses the biochemical mechanisms related to photosynthesis. Describes a water-oxidizing clock generating a molecule of oxygen with every four ticks. Lists four references. (YP)

Reviews various science activities investigating polarized light. (SL)

Describes experiments in which a ball bearing is used as a tool for the study of light and as a kind of photographic lens. Also shows how results from these experiments contribute to an understanding of the nature of light. (JN)

Discusses how the sun's reflection from water offers a means for calculating sloped of waves. Experiments using angles of reflection from a tilted mirror are suggested and explained. A method of counterbalancing dominoes in a stack beyond the edge of a table (using Euler's constant) is also described. (DH)

Presents the plans for constructing a spectrophotometer which can scan the spectrum in a thirtieth of a second. The instrument can be used to determine the absorption characteristics of a solution compared to a pure solvent. The instrument allows time to investigate phenomena that occur quickly. (Author/SA)

Provides background information on and experiments for determining the spectra of streetlights. Procedures for taking photographs of the spectra produced are included as well as discussions of sodium and mercury spectra. (JN)

Described is a way for an amateur to build a mercury-vapor ion laser which was devised by Dean Morelli. Morelli's laser emits bright pulses of green light and dimmer pulses of red-orange light and is the first gaseous-ion laser. (Author/DS)

Spatial filtering, based on diffraction/interference of light waves, is a technique by which unwanted information in a picture ("noise") can be separated from wanted information. A series of experiments is described in which students can create a system that functions as an optical computer to create clearer pictures. (Author/JN)

Describes several different philosophies of mind with each philosophy's explanation of the mind-body problem. Philosophies discussed include dualism, materialism, functionalism, radical behaviorism, logical behaviorism and central-state identity. (DS)

Introduces optical experiments and observations for an airplane passenger including scratches on a window, scattering of light, and reflection images. Provides several diagrams. (YP)