A history of measuring time

A history of measuring time

• Measuring the time in a year or a day has always been a priority

• People in ancient civilisations had sophisticated  to record the passing of time

Some ancient tools for measuring time

• Stonehenge: a 5000-year-old stone circle in England

• It was possibly built by druids (priests)

• The stones seem to have been erected for viewing the  on the solstice (the longest day of the year).

• In the past, days were divided into 12 periods

• Shadow clocks have been discovered in , which consisted of a large column
• Some were constructed out of , and were several metres in height

Water clocks

• These were used in various locations and had moving parts

• However, they were ineffective in  conditions
• Engineers in China addressed this problem by using mercury and  instead of water

Mechanical clocks

• The first known one was constructed in Germany in the 10th century

• In the 14th century, a clock with a  to mark the hours was constructed; this is still in Salisbury Cathedral, England

Further developments in clock making

• Clockmakers aimed to produce clocks that were  and able to tell the time more precisely, especially to aid sailors with navigation
• Thomas Tompion, an English clockmaker, managed to produce a clock that was small enough to be 
• Tompion gave one of these to an English