Sound resonance
To every system, if it is disturbed and let free to oscillate by itself, the system will oscillate at its natural frequency
e.g. pendulum
If a system is oscillating at its natural frequency, and energy is add to it at a frequency = natural frequency of the system
The system will absorb the energy at 100% efficiency
System will oscillate at increasing amplitude
What will happen then?
Sound + wine glass 1
Sound + wine glass 2
Tacoma Narrows Bridge Story
Musical notes and noises (Page 282)
•The waveforms of notes are regular.
•The waveforms of noises are irregular.
Tuning fork Mouth organ Noise
•The higher the frequency, the higher the
pitch.
•The loudness of a musical note is related to
the amplitude and frequency. For two musical
notes of the same frequency, the one with a
larger amplitude is louder.
• Different musical notes played by different
instruments have different waveforms and
thus different qualities.
CRO traces (by oboe)
CRO traces (by French horn)
Oboe 雙簧管 French horn 法國
號
Page 283
Ex. P.288 (5)