Timekeeping devices - Topics

How is the shutter time of a camera actually verified? Why does the sound of a ticking clock change how a room feels? Why does a pendulum clock run slow in a hot summer and fast in a cold room? Why do hourglasses survive in kitchens and board games when digital timers are cheaper? Why do quartz watches lose a few seconds a month no matter how fresh the battery is? What makes an atomic clock wrong by only one second in a hundred million years? Why does a smart speaker show the wrong time after a power cut even though it syncs over wifi? Millisecond pulsars keep time better than most man-made clocks What fails first in a clock that has run continuously for fifty years? How does a phone know the time when it has no signal at all? How do marathon timing chips actually record your finish? Why can a ship's clock not simply be a pendulum clock? Why did ancient China and Europe build water clocks for very different purposes? How do you measure a one-second interval with nothing but a piece of string and a weight? How accurate can a water clock get before dripping stops being reliable? Why does a sundial need a correction table to tell useful time? Why do some watch movements beat eight times a second instead of six? Why does a smartwatch battery last two days while a solar G-Shock runs for ten years? Why did early mains-powered clocks depend on the grid holding its frequency steady? Why does a cheap oven timer drift while a microwave timer looks fine? Who kept the time overnight in a medieval monastery? Why does a mechanical watch lose accuracy as the mainspring unwinds? Why did monasteries need precise time for prayer and what did they build for it? How does a city keep thousands of public clocks agreeing without anyone touching them?