Sonic Spectrum and Its Effects

Sonic Spectrum

• Sonic spectrum can be classified into three frequency ranges: infrasound, audible sound, and ultrasound, based on frequency and atmospheric pressure.
• Infrasound: less than 20Hz, produced by natural phenomena like earthquake waves and atmospheric pressure changes.
• Audible Sound: 20Hz to 20kHz, audible to the human ear.
• Ultrasound: greater than 20kHz.

Infrasonic Effect on the Human Body

• Infrasound can travel long distances without losing much power due to its low absorption and large wavelength.
• Infrasound can travel through most media, making it difficult to minimize its effects.
• Intense infrasonic noise causes clear symptoms including respiratory impairment and aural pain.
• Other potential effects include fear, visual hallucinations, and chills.

Applications of Infrasound and Ultrasound

• Infrasound is used to study heart mechanical function through seismocardiograms.
• Ultrasound is used clinically in several specialties, providing more information than X-rays and being less hazardous to the fetus.

Intensity of a Sound Wave

• Intensity of a sound wave (I) is the energy carried by the wave per unit area and per unit time (W/m²).
• Intensity can be expressed by the maximum change in the wave per unit area and per unit time (W/m²).
• The characteristics of a substance affect the intensity of a sound wave, with factors including density (ρ), velocity (v), and acoustic impedance (Z).

Explore the classification of sound waves into infrasound, audible sound, and ultrasound, and learn about the effects of infrasound on the human body.