Teacher Notes
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Teacher Notes
Publication No. 12772
Benham’s Disk Optical IllusionStudent Laboratory KitMaterials Included In KitBenham’s Disk Sheets, laminated, 8 Additional Materials RequiredColored pencils (optional) Prelab PreparationUse scissors to cut out each Benham's disk from the laminated sheets. A total of 16 Benham's disks can be prepared. Safety PrecautionsUse caution when handling the pushpins. Follow normal classroom safety guidelines. DisposalThe Benham’s disks can be reused many times. Remove the dry erase markings from the disks with a damp paper towel. Teacher Tips
Correlation to Next Generation Science Standards (NGSS)†Science & Engineering PracticesAsking questions and defining problemsPlanning and carrying out investigations Constructing explanations and designing solutions Disciplinary Core IdeasMS-PS4.B: Electromagnetic RadiationHS-PS4.B: Electromagnetic Radiation Crosscutting ConceptsPatternsCause and effect Energy and matter Answers to Questions
DiscussionIn 1894, the toymaker Charles E. Benham introduced his “Artificial Spectrum Top.” It later became known as the Benham’s top or Benham’s disk. When spun, the black and white top appeared to produce colored rings. The appearance of color is still a mystery even after more than 100 years, but it is believed to be at least partially the result of complex nerve responses in the cones of the retina. The cones of the retina allow individuals to see colors. Gustav Fechner (1801–1887), a German scientist and father of a branch of psychology known as psychophysics, was the first to describe the appearance of color from a spinning object in 1838. Psychophysics is the study of the relationship between stimulus intensity and a subjective experience (mental sensation) of the stimulus. The “pattern-induced flicker colors” that are produced by the Benham’s disk are known as subjective colors because the colors are perceived by our eyes due to the different response times of the cones of the retina. There are three color-sensitive cones on the retina—one for green, one for blue, and one for red. Each type of cone has different response and persistence times. For example, the “blue” cones have the slowest response times but they will continue to respond for the longest time after the stimulus has been removed. Teacher HandoutsReferenceshttp://www.michaelbach.de/ot/col_benham/ (Accessed June 2018) Recommended Products
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Student Pages
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Student PagesBenham’s Disk Optical IllusionIntroductionDisplay the colors of the rainbow on a rotating black-and-white disk. Concepts
MaterialsBenham’s disk blank cutout, laminated Safety PrecautionsUse caution when handling the pushpin. Procedure
Student Worksheet PDF |