TRIANGLES
acoustics
Description of the device
A triangle is a musical instrument used in percussion section of a symphonic orchestra.
Phenomenon
Vibrations caused by striking the triangle spread alongside its rod. When the vibrations reach one of the rod’s ends, they go backwards and superpose on the next vibrations that come from the source spot. As a result, a standing wave is formed.
How to use it
Strike the triangles with the beater. Examine how the pitch and timbre of the sound depend on the triangle’s size, the spot that is struck and the method of striking.