How do quartz and atomic clocks work, as Jim Bennett and Jonathan Betts explain them?

Jim Bennett said quartz clocks came from radio engineers who needed a standard frequency in the 20th century. A quartz crystal is piezoelectric, so bending it shifts electric charge, and an electric stimulus can keep it resonating at a steady rate. Jonathan Betts said atomic clocks from the 1950s refine quartz: caesium atoms pass through a microwave cavity controlled by the quartz and change state only at a very precise frequency, which lets the quartz be trimmed.

• Kristen Lippincott said the leap second worries her tremendously.
• Lippincott framed the choice as living by the sun, moon and stars or by intervals, and sided with the sky.

▸In their words

“It worries me tremendously, and we're now coming to the hairy topic of the leap second.” Kristen Lippincott · at 47:30 — open in the transcript →

Source: our own transcription of the episode. The full conversation is on In Our Time (2026-10-12). Read the whole episode summary →

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