CAASPP Success - Grade 3 Reading Comprehension - Expository #2

How People Have Told Time Through History

[1] Have you ever wondered how people knew what time it was before clocks and watches were invented? The way people have told time has changed a lot over the years. Let’s take a look at the history of telling time and how it all began.

[2] A long time ago, people noticed that the sun moved across the sky every day. They realized they could use the position of the sun to tell what time it was. This led to the creation of sundials, one of the earliest timekeeping tools. Ancient Egyptians were among the first to use sundials around 3,500 B.C. They even built tall structures called obelisks, which also worked as giant sundials, casting shadows to mark different times of the day.

[3] But what about when the sun wasn’t shining, like on cloudy days or at night? People invented other ways to measure time. The ancient Greeks developed water clocks, known as clepsydras, around 325 B.C. These clocks used water dripping from one container to another to measure time. The Greeks even added an early version of an alarm to their water clocks, where the rising water level triggered a whistle to alert people when a certain time had passed. Around the same period, the Chinese used candle clocks, which burned at a steady rate, allowing people to measure time during the night.

[4] In the Middle Ages, mechanical clocks were invented in Europe. The first mechanical clocks, built around the 1300s, used gears and weights to keep track of time. These clocks were large and often found in church towers or town squares. They were not very accurate at first, sometimes losing or gaining several hours each day. However, in 1656, the Dutch scientist Christiaan Huygens invented the pendulum clock, which greatly improved accuracy. Pendulum clocks became the standard, and for the first time, people could measure time within a few seconds of accuracy each day.

[5] As timekeeping technology improved, clocks became smaller and more portable. The first pocket watches were created in the 1500s in Germany. These early watches were not very accurate and needed to be wound regularly. By the 1600s, however, watches had become more reliable, and people began wearing them on their wrists. This invention laid the foundation for the wristwatches we use today.

[6] The 20th century brought even more advancements. In 1927, the quartz clock was invented. Quartz clocks use a tiny piece of quartz crystal that vibrates at a very precise frequency when electricity passes through it. This technology made clocks even more accurate, leading to the development of modern digital watches. Today, atomic clocks, which measure time based on the vibrations of atoms, are the most accurate clocks in the world, keeping time to within billionths of a second.

[7] Over thousands of years, the way we tell time has evolved from using the sun and stars to relying on incredibly precise technology. Each invention has helped us keep track of time more accurately, making it easier to organize our day and connect with others. So, the next time you check the time, remember all the amazing inventions that have made it possible!

In the Middle Ages, mechanical clocks were invented in Europe. The first mechanical clocks, built around the 1300s, used gears and weights to keep track of time. These clocks were large and often found in church towers or town squares.

"In 1656, the Dutch scientist Christiaan Huygens invented the pendulum clock, which greatly improved accuracy. Pendulum clocks became the standard, and for the first time, people could measure time within a few seconds of accuracy each day."