Sound Quotes

“If one wishes to ‘see’ a travelling wave, one must therefore chart air pressure changes through time. One of the first to attempt this was Alexander Graham Bell, who in 1874 procured an ear from a corpse, impregnated it with oil to keep it flexible, and attached a thin straw to its drum. The other end of the straw was allowed to trace a line on a strip of soot-covered glass which was moved along as the ear was shouted at. This wobbly line was the first recording of a sound wave and the device was called an ear phonautograph. To the relief of those who had to construct them, later versions dispensed with dead ears in favour of metal diaphragms.”
― Mike Goldsmith, Sound: A Very Short Introduction

“The deep sound channel was exploited to set up the SOFAR (sound fixing and ranging) system, which was initiated in 1960 by the Australia-Bermuda Sound Transmission Experiment, in which explosions were set off near Heard Island in the Indian Ocean off the coast of Australia. They were detected in Bermuda, at a distance of 20,000 km. A new, unexpected sound was discovered by the SOFAR researchers, and later identified as the calls of fin whales (Balaenoptera physalus), who long ago discovered the existence and properties of the deep sound channel and regularly visit it to signal their distant kin.”
― Mike Goldsmith, Sound: A Very Short Introduction

“The distances over which sound can travel underwater are amazing. It is believed that before the proliferation of engine-powered vessels, Antarctic whales could be heard by their Arctic cousins. Such vast ranges are possible partly because sound waves are absorbed far less in water than in air. At 1 kHz, absorption is about 5 dB/km in air (at 30 per cent humidity) but only 0.06 dB/km in seawater. Also, underwater sound waves are much more confined; a noise made in mid-air spreads in all directions, but in the sea the bed and the surface limit vertical spreading.”
― Mike Goldsmith, Sound: A Very Short Introduction