Acoustics is the science of sound.

The term in the sense of a scientific discipline was first coined as the French term acoustique in an article published in 1701 by Joseph Sauveur, who stated (in this English translation): "I have formed the opinion that there is a higher science than music, and I call it acoustics; it has for its object sounds in general, whereas music has for its object sounds pleasing to the ear. To treat this science as other sciences, such as optics, it is necessary to explain the nature of sound, the organ of hearing, and all the properties of sound."

Advances in instrumentation made possible the systematic study of sounds (infrasound and ultrasound) with frequencies lower and higher than humans can hear, and it was recognized that the same physical principles are applicable.

New tools, called digital acoustic recording tags, are attached to whales with suction cups and track them throughout dives. Tag measurements are the result of collaboration: Engineer Mark Johnson designed and built the tags; Biologist Michael Moore developed the method of using a cantilevered carbon-fiber pole to touch an instrument to a whale; Johnson and Tyack adapted the pole for attaching tags (below).

It’s an adventure steering a boat close to an unsuspecting whale and with a 40-foot pole attaching a tag and hoping the whale won’t notice. Sperm whales are not noted for friendly behavior toward boats. “Before I started doing this,” Tyack said, “I spent a day at the New Bedford Whaling Museum, reading records of sperm whale attacks."

”Luckily, whales don’t react to the tags. They are small—like a flea on a Great Dane—but huge in storage capacity. Time, depth, fluke beats, body orientation, sounds the whale makes, and ambient sounds are all stored. After an hour or two, the suction cup releases and the tags, and their data, are retrieved."

The unit of acous- words is available at this link.