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)

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)

Outlines a simple classroom demonstration that illustrates Piagetian conservation. Piagetian conservation refers to the illusion of an increase in mass by changing an object's form. This demonstration, done by forming an ellipse with an extension cord, shows that college students are as susceptible to this effect as are young children. (MJP)