clepsydra

Everyday

A water clock: an ancient device that measures time by how much water drips into or out of a container. tree →

In the lessons

In history and science lessons about time it shows how people in ancient Egypt, Greece and China measured time before mechanical clocks. Ancient Athenian courts used one to time speeches. Phrases: "a water clock (clepsydra)".

Examples

• A clepsydra measures time with dripping water. tree →
• Ancient Egyptians used a clepsydra at night when sundials didn't work. tree →
• We built a clepsydra from a plastic cup with a hole. tree →
• In Athens, a clepsydra timed each speaker in court. tree →
• Marks on the clepsydra showed how many hours had passed. tree →

Note

Pronounced "KLEP-sid-ra". From Greek for "water thief". In maths: if water drips at a steady rate, the time is in proportion to the amount of water, so double the water means double the time.