Because the Earth rotates around its axis once a day, it is divided into 24 different time zones.  UTC (Coordinated Universal Time) is the world’s standard of time. It shows the time along the Earth’s  prime meridian. Theoretically, every 15° east or west of Greenwich means one hour more or less. In practice, however, time zones do not go through the middle of countries. 


Larger countries that span thousands of km, for example Russia or the United States, have several time zones.  On the other hand, the Chinese Communists changed to one time zone when they took over after World War II.


The world's time zones

The world's time zones
Image:Goran tek-en, CC BY-SA 4.0,
via Wikimedia Commons 



Words

  • axis = line around which the Earth spins
  • divide = split, separate
  • however = but
  • in practice = in the real world
  • rotate = go around
  • several = some, a few
  • span = stretch across
  • take over = get control of
  • theoretically = in theory
Last modified: Wednesday, 13 May 2026, 7:26 PM