Who Invented the First Alarm Clock in Ancient Greece?

Did you know that the concept of alarm clocks dates back to ancient Greece? Yes, you read that right!

The first alarm clock was invented in ancient Greece. In this article, we will delve deeper into the history of alarm clocks and explore who invented the first alarm clock in ancient Greece.

Ancient Alarm Clocks

In ancient times, people used various methods to wake up early in the morning. One of the most common methods was to use a water clock.

A water clock, also known as a clepsydra, was an instrument that measured time by marking the regulated flow of water from one container to another. However, this method had its limitations and wasn’t very reliable.

Ancient Greek Alarm Clock

The first mechanical alarm clock was invented by Ctesibius of Alexandria, who was a Greek inventor and mathematician. He lived in Alexandria during the 3rd century BC and is considered to be one of the most important inventors of his time.

Ctesibius’s alarm clock was known as the “hydraulis,” which means water organ. It worked on a similar principle as a water clock but had an additional feature that allowed it to make noise at a predetermined time.

The “hydraulis” consisted of a water tank with a float on top that rose gradually as the tank filled with water over time. When the float reached a certain level, it triggered a mechanism that played music or made some other sound.

How did it work?

The “hydraulis” had two containers – one for water and another for compressed air. The compressed air container had two openings – one for releasing air and another for filling it with water from the water container.

When someone wanted to set an alarm using this device, they would fill up the compressed air container with water from the other container until it reached a certain level. The compressed air would then push the water out of the container through a whistle or flute, creating a loud noise that could wake up even the soundest sleeper.


In conclusion, Ctesibius of Alexandria is credited with inventing the first mechanical alarm clock in ancient Greece. His “hydraulis” was an ingenious device that used water and compressed air to create a loud noise at a predetermined time.

Although this device was not widely used, it laid the foundation for modern alarm clocks that we use today. We hope you enjoyed reading about the history of alarm clocks!