Night and Day
In the direction towards the Sun the Earth is illuminated: it is day on that side, and away from the Sun, it is dark: it is night on that side. In a period of 24 hours, the shadow side rotates around the Earth and we all experience night and day.
But if you live e.g. in Europe your day will be at the same time that people in say the Pacific, experience night. Therefore we use time zones so that the Sun is at its highest point in the sky (midday) at about 12 noon local time for everybody.
World Time Zones
Hover your mouse over a time zone of interest.
Here you see western Europe from space on the edge between light and dark.
Question: Are the people living here awaiting sunrise or is it evening here? (Answer on next page).