Discusses the size-weight illusion that occurs when a person lifts two equal-weight objects differing in size and perceives the larger object as lighter than the small object. Describes several inexpensive techniques for demonstrating the size-weight illusion and reviews some relevant issues concerning this phenomena. (MJP)

Describes the rationale for using computer-assisted videodisc lessons to enhance introductory chemistry courses at University of Illinois, and presents sample lessons to illustrate what students see and do as they proceed through the lessons. Lesson construction and use are reviewed. (MBR)

Maintains that having students estimate the size and width of a class waste paper can (placed on a desk) is a simple and effective way of illustrating perceptual distortion. Tests show that people will consistently overestimate the height of the can, allowing for a useful discussion on sensory distortion. (MJP)