Introduction to optics

Deals with the approximation that light travels in straight lines and shows four ways in which light can be sent--diffraction, scattering, refraction, and reflection. Diffraction is shown using point light sources, a wide screen, and a variable slit. Scattering is observed in a smoke-filled box. Refraction and reflection are shown using an optical tank and also an under-water camera to observe the appearance of several swimmers sitting alongside the pool; effects illustrated include image displacement, the critical angle, and total internal reflection. Concludes with the problem of why the images produced by three pinholes merge into one when intercepted by a lens. Demonstrations by Elbert R. Little, PSSC.