Time Zones  Strange things happen to time when you travel. Because the earth is divided into twenty-four zones one hour apart .You can have days with more or fewer than twenty-four hours, and weeks more or fewer than seven days. If you make a five-day trip across the Atlantic Ocean ,your ship enters a different time zone every day. As you enter each zone, the time changes one hour. Travelling west ,you set your clock back; traveling east , you set it ahead. Each day of your trip has either twenty-five or twenty-three hours. If you travel by ship across the Pacific , you cross the international date line. By agreement, this is the point where a new day begins, when you cross the line, you change your calendar one full time day, backward or forward. Travelling east, today becomes yesterday; traveling west, it is tomorrow. The international date line is the name for  _  .
the beginning of any new time zone the point where a new day ends the point where a new day begins any time zone in the Pacific Ocean