Assertion: atomic clock | /r/HasProperty | invented
Facets:
Source sentences:
text: Sine 1949 when the first atomic clock was invented, there are many types of atomic clock being made.
text: The atomic clock was invented and announced by Harold Lyons, the Microwave Standards Section Chief at NBS, (National Bureau of Standards) and his team in 1949.
text: The atomic clock was invented out of need for a timing standard that would allow radio stations to stay on their assigned frequency.