Website
Physics Classroom

The Physics Classroom: Sound Wave and Music Table of Contents

For Students 9th - 10th
Learners investigate the nature of a sound wave, sound properties, resonance, musical instruments, and standing waves. The tutorial consists of lessons and problems to check for understanding.
Website
Ministerio de Educación (Spain)

Ministerio De Educacion: Musica Educa (Spanish)

For Students 3rd - 5th
This site is about music in general to be viewed by children as something natural and easily accessible. It contains various interactive activities with sound files and also an application to color.