🚀 Inventions and machines 🔧 Machines and tools

Clocks

📖 In short

A clock is a machine that tells us the time. We look at it to know when to go to school, when to pray and when to sleep. There are big wall clocks, small wristwatches and digital clocks that show only numbers.

🤩 Did you know?

Sundials were made about 4000 years ago.
Most quartz clocks are accurate to within a minute a year.
The first mechanical clocks in Europe had no hands and rang the hour with a bell.
London's “Big Ben” is one of the most famous tower clocks.

🔎 Find out more

🌟 Old clocks

Thousands of years ago people used the sundial, a stick whose shadow moves with the sun to show the time. They also used water clocks, where water drips, and hourglasses.

🔍 The Elephant Clock

More than 800 years ago the Muslim engineer al-Jazari built amazing water clocks, the most famous being the “Elephant Clock”, with an elephant, birds and figures that move and make sounds every half hour.

💡 Hands and numbers

On a clock with hands, the short hand shows the hours, the long hand the minutes, and the thin fast hand the seconds. Your day has 24 hours.

🎯 Very precise clocks

Today many clocks have a tiny quartz crystal that vibrates amazingly evenly, making them very accurate. And there are atomic clocks that are only off by one second in millions of years!