WHERE WE KEEP TIME Time is something which we hav e been curious about since the day we discov ered change. Time stays with it and we k ee p it.
DAYS DIVIDE Five thousand years ago, Sumerians in the Tig ris-Euphrates valley in today’s Iraq had a calendar that divided the year into 30 day months, divided the day into 12 periods (each corresponding to 2 of our hours), and divided these periods into 30 parts (each like 4 of our minutes).
MESOLITHIC PERIOD “Ice-age hunters in Europe over 20,000 years ago scratched lines and gouged holes in sticks and bones, possibly counting the days between phases of the moon.”
NIST
1500 CE
18000 BCE 3000 BCE
NIST
MECHANICAL MOVEMENTS In 1656, Christiaan Huygens, a Dutch scientist, made the first pendulum clock, regulated by a mechanism with a “natural” period of oscillation. (Galileo Galilei is credited with inventing the pendulum-clock concept, and he studied the motion of the pendulum as early as 1582. He even sketched out a design for a pendulum clock, but he never actually constructed one before his death in 1642.) Huygens’ early pendulum clock had an error of less than 1 minute a day, the first time such accuracy had been achieved. His later refinements reduced his clock’s error to less than 10 seconds a day. NIST
WHO HAS THE CORRECT TIME? All included information is from The National Institute of Standards and Technology (NIST) an agency of the U.S. Department of Commerce.
2000 CE