Atomic clock film from the 1950s
A film has come to light that was produced by the NPL Film Unit in the 1950s.
The film explains the principles behind the first accurate atomic clock, designed by Louis Essen and built at NPL in 1955. Watch the film below:
We are very grateful to Ray Essen, Louis Essen's son-in-law, for unearthing this piece of NPL's history.
More on the world's first accurate atomic clock
Explore our pages on Time
Further details about the history of NPL