Alarm Clock
Alarm Clock Going Off [Image via Bustle]

39. The Alarm Clock

  • Time of Invention: 428 B.C.

No need for batteries or electricity, the Greeks found a way to make an alarm clock without it. Greek Philosopher Plato was among the most notable to have one. He had a water clock that acted as an alarm system, which set off a signal to the sound of a water organ.

Many believe that he used this to signal the start of his many lectures each day. It is said that the system was perfected when Ancient Greek & Egyptian Engineer Ctesibius made his version. His machine made pebbles drop down to create a gong or blow trumpets by using compressed air or water. They’d go off at different pre-set times during a given day, creating the version we know today.