1490 – First reports
Leonardo da Vinci writes the first reports of listening to sound under water. “If you cause your ship to stop and place the head of a long tube in the water and place the outer extremity to your ear, you will hear ships at a great distance from you.”
1687 – Sound and mathematics
Sir Isaac Newton first describes sound in mathematical terms.
1829 – Underwater measurements
Physicist Jean-Daniel Colladon and mathematician Jacques Charles François Sturm make the first measurements of the speed of sound under water.
1850 – Helmholtz resonator
German physician and physicist Hermann von Helmholtz designs the first Helmholtz resonator.
1857 – Hertz born
The birth of German physicist Heinrich Rudolf Hertz – a founder of the field of electromagnetic theory and namesake for the hertz unit.
1912 – Submarines
Technology for listening for submarines under water is developed and deployed for the first time.
1919 – First scientific paper
The first scientific paper on underwater acoustics is published.
1923 – Bel
The transmission unit (TU) is renamed the ‘bel’ in honour of the founder of Bell Laboratories, Alexander Graham Bell.
1946 – Physics of sound
The book Physics of Sound in the Sea is published as a summary of advances in the field during World War II.
1946 – Oscilloscope
Americans Howard Vollum and Jack Murdock develop the triggered oscilloscope – the forerunner to the modern oscilloscope.
1958 – Underwater recording station
The New Zealand Navy places a permanent underwater recording station on Great Barrier Island in the Hauraki Gulf.
1960 – Hertz becomes standard unit
The General Conference on Weights and Measures adopts the hertz as the standard unit for measuring the frequency of sound, replacing cycles per second (CPS).
1962 – Evening chorus
New Zealand scientists identify the ‘evening chorus’ and propose kina as the source of the increase in underwater reef sound at dusk.
2008 – Kina and noise
Researchers from the Leigh Marine Laboratory conclusively show the role of kina in the production of reef noise.
2010 – Crab larvae and noise
Researchers from the Leigh Marine Laboratory publish their studies on the settlement and metamorphosis of crab larvae in response to reef noise.
