Who discovered the speed of sound?

Short answer

No one discovered it all at once. Marin Mersenne and Pierre Gassendi measured it in the 1630s by timing the flash and bang of gunfire; the Accademia del Cimento and William Derham (1709) refined the value to about 350 m/s. Newton calculated it in 1687 and Laplace corrected his formula in 1816.

Published: September 21, 2026 · Updated: September 21, 2026 · Edited by Above Ten Thousand · Editorial policy

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The first measurements, with gunpowder and a clock

The idea that sound takes time to arrive is ancient: anyone who watches a distant lightning bolt fall can confirm it. But putting a number on it required instruments that didn't exist until the 17th century. Marin Mersenne, a Minim friar and correspondent to half of scientific Europe, published a value around 1636 obtained by measuring the delay between the flash and the bang of a firearm at a known distance; Pierre Gassendi did the same and also found that low and high-pitched sounds arrived at the same time, which ruled out an old Aristotelian belief. Both men's values were around 450 m/s, a third above the real figure, because the pendulums and clocks of the time were crude and wind wasn't corrected for.

Fine-tuning the number

The Accademia del Cimento in Florence, with Borelli and Viviani, repeated the experiment in the 1660s with better timekeeping and obtained figures close to 350 m/s. The decisive step was taken by the Reverend William Derham, who between 1704 and 1708 observed cannon shots fired several kilometers away from the tower of Upminster church, averaged many measurements under different wind conditions and published in 1709 a value that, converted, equals about 348 m/s: practically today's figure for air on a mild day. Derham was also the first to systematically document that speed didn't depend on the loudness of the sound or its direction, but did depend on the wind.

The theory: Newton and Laplace

Isaac Newton, in the 1687 Principia, was the first to derive the speed of sound from the properties of air and obtained about 298 m/s, 15% below the measured value. The discrepancy was puzzling for more than a century, until Pierre-Simon Laplace, in 1816, pointed out that the wave's compressions happen so fast that the air has no time to exchange heat: the process is adiabatic, not isothermal, and Newton's result must be multiplied by the square root of the ratio of specific heats. With that correction the formula matched the experiments, and it's the one used today by the air data computers of any jet.

From the laboratory to Mach 1

Ernst Mach photographed the shock waves of supersonic projectiles in the 1880s, and from him comes the name of the ratio between an object's speed and that of sound. When the Bell X-1, piloted by Chuck Yeager, exceeded Mach 1 in 1947, the number it crossed carried three centuries of measurements behind it: from Mersenne's gunshot flashes to the temperature probes that today calculate the local speed of sound several times a second.