The Earth is known to turn on a an imaginary pole which is actually called its "axis." Every 24 hours, the Earth makes an entire pivot — or one full turn — on its axis,we consider each full turn to be called a day.
Envision sparkling an electric lamp at a globe. Just piece of the globe would get light, while the contrary side of the globe would be dull. As the Earth turns, distinctive parts of the Earth get daylight or dimness, giving us day and night.
As your area on the Earth pivots into daylight, you see the sun rise. At the point when your area turns out of daylight, you see the sun set.
On the off chance that we had one single time zone for Earth, twelve o clock noon would be the center of the day in a few spots, yet it would be morning, evening and the center of the night in others. Since various parts of the Earth enter and leave sunlight at various occasions, we require diverse time zones.