|Sam Gale, a test reader & evaluator from Kernersville, NC
||Doug Behrend, a college professor from Fayetteville, AR
||Sarah Thompson, an art history professor from Rochester, NY (1-day total: $16,999)
Scores going into Final Jeopardy:
Final Jeopardy! category: 20TH CENTURY INVENTIONS
Final Jeopardy! clue: In the 1950s physicist Louis Essen built the first practical one of these, noting that it wouldn’t give you the time of day
What is an atomic clock?
Sam 7000 + 2900 = 9900
Sarah 8200 + 6000 = 14200
Doug 9200 + 7201 = 16401 (1-day total: $16,401)
Regarding the clue? Ba-dum-tish! I eventually stopped groaning long enough to put the correct response down to Final Jeopardy.
Meanwhile, From the Royal Society of Chemistry:
Essen learned about the abortive experiments on a visit to Washington in 1950. He returned to the UK convinced that he could build a better clock by combining Rabi’s atomic beam methods with his own quartz timekeeper. He chose caesium because the hyperfine coupling between its single valence electron and nucleus gave a pair of conveniently separated spin states with long lifetimes. He packed a version of Rabi’s apparatus into an evacuated 1.5m tube, with the improvement of Norman Ramsey’s U-shaped microwave cavity providing two excitation regions and thus much narrower signals. The detector was now connected to a clock built from one of Essen’s quartz rings, kept precisely in time by linking it to the rf field in a feedback loop. Any slowing of the ring’s rhythm would pull the rf field off resonance, causing a change in the detected signal and automatically triggering a correction of the beat. His first clock kept time to within one second in 300 years; Essen was so excited that he dragged the director of the NPL [National Physical Laboratory] ‘to witness the birth of atomic time’.
(contestant photo credit: jeopardy.com)
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