The Nature Songs website offers a variety of natural sounds, including animals, wind and waves, and also offers advice to those who want to record sounds from nature.
Learn how languages around the world express the sounds animals make from this Georgetown University site.
This Exploratorium site tells you how to make a musical instrument from everyday food cans.
Find basic concepts about light, optics and telescopes, and access resources for teachers at the Amazing Space website.
This great how-to site from Exploratorium teaches about mixing colors, and explains some of the theory behind how colors are made and how we see them. (Requires Macromedia Shockwave.)