Physics Classroom
The Physics Classroom: Reflection and the Ray Model of Light
A four-lesson tutorial on the reflection and the ray model of light. These complete tutorials include informational text, interactive activities, animations, and quick, interactive comprehension questions.
CK-12 Foundation
Ck 12: Physical Science: Lens
[Free Registration/Login may be required to access all resource tools.] What a lens is and what it does, concave and convex lenses.
Boston University
Bu: Optics: Geometric Optics
Several short descriptions of demonstrations which illustrate principles of geometric optics (many of which focus upon refraction).
Other
Geometric Optics
This site provides a very brief definition to geometric optics, and includes links to related information.
ClassFlow
Class Flow: Introduction to Light
[Free Registration/Login Required] This flipchart introduces fifth graders to the science of light. Principles such as transparent, translucent, opaque, reflection, and refraction are covered. Concave and convex mirrors and lenses are...
Optical Society
Optical Society of America: Optics for Kids: Lenses and Geometrical Optics
Article explaining what lenses are and how they work. At the end of the article, there are links to several hands-on activities for investigating lenses.