Academic Reading
Keeping time: the history of the clock
AFor most of history, people told the time by the Sun, using shadow clocks and sundials that were useless at night or on cloudy days. Water clocks, which measured time by the steady dripping of water, offered an early solution to this problem.
BA great leap came with the invention of mechanical clocks in medieval Europe, driven by weights and gears. Later, the pendulum made clocks far more accurate. Today, atomic clocks are so precise that they would lose less than a second over millions of years, and they underpin technologies such as satellite navigation.