ammonia clock

9.1

A clock that uses the vibration of nitrogen in an ammonia molecule to keep very exact time

noun
/əˈmoʊniə klɑk/

Specialized

: reloj de amoníaco

An ammonia clock measures time by analyzing the vibrations of nitrogen atoms within ammonia molecules.

Examples

Scientists first used the ammonia clock in the 1940s to demonstrate the principle of atomic time measurement.
The ammonia clock was a precursor to modern atomic clocks used for precise timekeeping.
Although less accurate than newer models, an ammonia clock played a crucial role in the development of time standards.
The ammonia clock is highly accurate.
Did you hear about the new ammonia clock?
In the 1950s, researchers improved precision in navigation by using an ammonia clock for exact time measurement.
The development of the ammonia clock marked a significant advancement in scientific understanding of atomic properties.

Synonyms

atomic clock

vsammonia clock

Specialized

5 4.3

A very accurate clock that uses atoms to measure time

measures one specific molecular vibration rather than general atom oscillations

Surface Forms

ammonia clock singular

ammonia clocks plural

Morphology

ammonia + clock

At a basic level the compound is compositional: a B1 learner who knows 'ammonia' and 'clock' can infer it is a clock that involves or uses ammonia, so the general idea is accessible. However, the precise technical sense — an atomic clock measuring a specific molecular vibrational frequency — is specialized and not derivable from the words alone. Because the general referent is transparent but the detailed technical mechanism is not predictable, this is best classified as semi-transparent.

Etymology

The noun ammonia clock comes from using the steady vibration of the ammonia molecule like a tiny clock tick. Scientists measured the nitrogen atom's regular movement to mark time, so the name means 'a clock that keeps time by ammonia vibrations'.