Loudness
Explanation
Sound is a mechanical wave produced by vibrating objects. The characteristics of sound-loudness, pitch, and quality-are determined by specific properties of the wave, such as amplitude, frequency, and waveform.
Analysis of Physical Quantities:
- Loudness: This characteristic is determined by the amplitude of the sound wave. Amplitude refers to the maximum displacement of the particles of the medium from their mean position. The loudness of sound is directly proportional to the square of the amplitude of the vibration ($L \propto A^2$). If the amplitude is doubled, the loudness increases by a factor of four.
- Pitch: This characteristic determines the shrillness or flatness of a sound and is determined by the frequency of vibration. A higher frequency results in a higher pitch (shriller sound), while a lower frequency results in a lower pitch (deeper sound).
- Quality (Timbre): This characteristic allows the ear to distinguish between two sounds of the same pitch and loudness. It is determined by the waveform or the presence of overtones (harmonics).
- Speed: The speed of sound depends on the properties of the medium (such as elasticity and density) and environmental factors like temperature and humidity, not primarily on the wave's amplitude.
Key Takeaway:
Loudness is a measure of the sound energy reaching the ear per second and depends on the amplitude of the wave. Pitch depends on the frequency.