SkyServer answers why stars have different colors and shows what you can learn by studying the colors of stars, galaxies, and other objects.

This lesson will introduce the shape of waves, including amplitude and frequency. It will also describe how the shape of waves changes from one type to the next. It is 5 of 5 in the series titled "Wave Shape."

This lesson will introduce the shape of waves, including amplitude and frequency. It will also describe how the shape of waves changes from one type to the next. It is 1 of 5 in the series titled "Wave Shape."

Take this ten question multiple choice quiz on the main concepts of light.

A simple activity to demonstrate how light separates into colors when it passes through water acting as a prism.

What is light? Illustrated discussion of the speed of light, how we see colors, and how light helps us.

This Imagine the Universe site provides an introduction into the multiwavelength universe and astronomy. Site provides graphics, links to a quiz, facts on this topic as well as teacher resources.

A quiz on color complements and basic facts about color. Click back to home to access the French- or Spanish-language version of the site.

In addition to defining and describing obsessive-compulsive disorder (OCD), this website provides explanations as to why OCD is often misdiagnosed. Learn what "obsessions" and "compulsions" are and learn how to detect the signs and...

This page is a detailed historical overview of United States soccer from its roots in the 19th century to the present day.