University of Oregon
Determining Properties of Stars
An excellent website detailing how a star's properties can be determined, and how these properties lead to the way a star is classified.
Other
National Optical Astronomy Observatory: Jewels of the Night
Using the Jewelbox Cluster, learners determine the cluster's age based on measurements of its color and brightness.
NASA
Nasa: Imagine the Universe: How Big Is That Star
This 2-5 day lesson plan investigates the diameter, radius and mass among several stars in order to understand stellar behavior, particularly in a binary system.
NASA
Nasa Star Child: Stars
This page details the life cycle of a star, and includes information on medium-sized and massive stars, plus a glossary and a question.
Other
Sky Server: Types of Stars
SkyServer of the Sloan Digital Sky Survey shows you the different types of stars as well as how to classify and identify them.
Other
Sky Server: Color
SkyServer answers why stars have different colors and shows what you can learn by studying the colors of stars, galaxies, and other objects.