written by Rebecca E. Vieyra
sub author: Caroline Hall

This lesson blends physics, geometric optics, and biology as students explore light refraction through convex and concave "lenses" made of clear gelatin. The activity promotes understanding of four key concepts: 1) convex lenses cause light to converge, while concave cause divergence; 2) Focal length can be determined from the convergence point of a convex lens; 3) Ray diagrams provide a geometric way to depict the path of light through a transparent object; and 4) The malleable gelatin lenses can model the function of the human eye.

This AAPT Lesson Plan was inspired by two articles in The Physics Teacher magazine: "Edible Optics: Using Gelatin to Demonstrate Properties of Light" by Patrick Bunton, and "Construction of Optical Elements with Gelatin" by Mario Branca and Isabella Soletta.

• Download FINALTeacherGuide-GelatinLens_RVieyra-CHall-2021Update.pdf - 512kb Adobe PDF Document

Released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license.

Published January 8, 2017
Last Modified October 28, 2021

This file has previous versions.

by R. Vieyra and C. Hall

Teacher's Guide: Modifiable Word document: Customize and Print Your Lesson

• Download FINALTeacherGuide-GelatinLens_RVieyra-CHall-2021Update.docx - 4873kb Word Document

Released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license.

Published October 10, 2017
Last Modified October 28, 2021

by R. Vieyra and C. Hall

Student Worksheet: Modifiable Word document  
Background information and problem set

• Download FINALStudentGuide-GelatinLens_RVieyra2017January.docx - 4230kb Word Document

Released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license.

Published October 10, 2017
Last Modified October 28, 2021