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University of New South Wales (Australia)

University of New South Wales: Introduction to Acoustics of Brass Instruments

For Students 9th - 10th
Discover the acoustical properties of brass instruments from this well researched site provided by the University of New South Wales. Everything from lip control to bell shape is discussed as it applies to frequencies and harmonics.
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Mocomi & Anibrain Digital Technologies

Mocomi: Types of Musical Instruments

For Students 2nd - 8th
Provides a list of musical instruments and how they work.
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OpenStax

Open Stax: Catherine Schmidt Jones: Orchestral Instruments

For Students 9th - 10th
This is a brief introduction to the various instruments on the modern orchestra. It is broken into sections based on the instrument families. Each instrument is briefly defined.