This webpage thoroughly discusses the math of spheres. Includes the equation for a sphere in Cartesian and spherical coordinates as well as parametrically. Surface Area, volume, and curvature are addressed at this extensive site.

This site shows what a diameter is, how to find one on a circle or a sphere, and provides the formula to find diameter of a circle or "the great circle of a sphere.

In this video segment [3:10] from Cyberchase, the CyberSquad must find the exact center of a circle in order to save Motherboard.

[Free Registration/Login Required] In this flipchart, students develop an understanding of the properties of a sphere and determine its area and volume.

Straightforward lesson that introduces students to pi by letting them measure real objects and solve a challenge problem. Includes instructions and a "Data Sheet" for keeping track of measurements. Available in English and Spanish.