Definition

Noun: - A scientific instrument for measuring sound particle velocity: A Rayleigh disk is a type of acoustic radiometer. It consists of a lightweight, circular disk suspended by a very thin quartz fiber. When placed in a sound field, the disk experiences a torque (a twisting force) due to the sound pressure. By measuring this torque, the velocity of the sound particles in the wave can be determined.

Usage

• The term is used in the context of acoustics, physics, and scientific instrumentation.
• It typically functions as the subject or object in a sentence describing measurement or function.

Examples

Advanced Usage

• "Rayleigh disk method": Refers to the experimental technique or procedure using this instrument.
  • The Rayleigh disk method provides a fundamental means of acoustic measurement.

Variants and Related Words

• Acoustic radiometer: The general category of instruments for measuring sound energy or related quantities, which includes the Rayleigh disk.
• Quartz fiber torsion balance: Describes the key suspension mechanism of the instrument.

Synonyms

• Acoustic velocity sensor: A more general modern term for devices that measure sound particle velocity.
• Sound radiometer: A broader, less specific synonym.

Notes on Meaning

• The term is highly specialized and refers to a specific historical and scientific apparatus. It is not used in everyday language.
• Its meaning is directly tied to its physical components (light disk, quartz thread) and its function (measuring torque to determine velocity in a progressive sound wave).

Noun

1. an acoustic radiometer consisting of a light disk suspended from a quartz thread; when exposed to a progressive sound wave its torque can measure velocity