Sound is not an entity but a pressure wave
Sound is not an object that “moves forward”, but a vibration transmitted from person to person. Think of it as a compact line of people, each transmitting an impulse to the next. The disturbance propagates, but no particle actually moves over a great distance. This collective mechanism explains how sound waves travel through air, water or solids.
The physical parameters that determine the speed of sound
The speed of sound depends on two main physical quantities:
The stiffness of the medium: the more rigid a material, the faster it transmits disturbances.
Particle inertia: the more massive the particle, the longer it takes to react.
These concepts are translated into measurable parameters: modulus of elasticity (or modulus of compressibility for fluids), noted K, and density, noted ρ.
The resulting formula is as follows:
v = √(K/ρ)
where v is the speed of sound.
A few orders of magnitude in different environments
In air, low particle density and high compressibility result in a velocity of around 343 m/s. In water, although the molecules are more massive, the medium is much less compressible, raising the speed to 1,500 m/s. In steel, density is high, but rigidity is even higher, and the velocity reaches around 5,000 m/s.
In a vacuum, on the other hand, there are no particles to transmit the vibration, so there is no sound.
The speed of sound in everyday life
The speed of sound isn’t just a theoretical concept: everyone experiences it when they see a thunderstorm. Lightning, which is a discharge of light, travels at the speed of light (300,000 km/s), so is almost instantaneous to our eyes. Thunder, produced by the shock wave in the air, takes longer to arrive, travelling at around 343 m/s. If we count three seconds between the flash and the roar, we can estimate that the lightning has fallen about one kilometer away.
Groupe BOËT expertise in industrial acoustic solutions
This understanding of the behavior of sound waves is not just theoretical: it forms the basis of the industrial acoustic solutions designed by Groupe BOËT. By taking into account the physical laws governing wave propagation, the company develops industrial silencers, Acoustic enclosures and customized equipment capable of ensuring lasting noise reduction. Quality certifications(ISO 9001, ISO 19443, EN 15085, ASME, RCC-M, CODAP, CODETI) guarantee the reliability and conformity of our solutions.
Conclusion: transforming acoustic science into concrete solutions
The speed of sound perfectly illustrates that acoustics is a science directly applicable to industry. Understanding how waves propagate in different media enables us to design equipment adapted to the most stringent acoustic constraints. The Groupe BOËT transforms this expertise into concrete solutions, offering its customers certified, tailor-made noise control.
