[Free Registration/Login Required] This flipchart defines a polygon and the classification of concave and convex polygons.

The dynamics of shape in art and the relationship of shape with the other elements of art. The effects of angles and lines on perception.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to classify a polygon based on its sides and how to determine whether a polygon is convex or concave.

This site gives the general definition of a nonagon with examples of a regular (convex) and irregular concave nonagons. There are links to related terms, challenging problems, more information, and the interactive check point involving...

This site provides a very brief definition to geometric optics, and includes links to related information.

Included here are illustrations of reflections from a plane mirror, a concave mirror and a convex mirror.

A simple activity to investigate how light reflects off a flat surface, a convex one, and a concave one. With a link to an article on reflection.

This site provides a basic experiment that shows how a lens works. This lesson plan explains nearsightedness and farsightedness. It also explains concave and convex lenses.

An experiment using Jell-O to create lenses, to see how light behaves with flat, concave, and convex lens surfaces. With an explanation of what is observed, and a link to an informative article on lenses.

This lesson will describe what a lens is and how a lens works.

This article from Khan Academy provides information about mirrors. This information is intended for the Class 12 Physics Course (India).

This site provides a definition for plane figure (at the top of the page) and a few examples.

Polygons for kids. Learn how they work, terms, tricks and examples. Regular, convex, concave, complex, and more.

[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...