Time zones were created because of Earth’s rotation. The sun illuminates the Earth, but only one portion at a time. Since the sun can’t rise in every part of the world at once, time zones maintain logical order and regulate day and night across the globe. Without time zones, we might have sunrise at 3 o’clock in the morning!
The continental United States has four time zones. But the country and its territories have others, including Hawaii Aleution Time and Alaska Time. France has territories all over the world, so it has 12 time zones, the most of any country.
Time zones typically follow longitude, but sometimes they can be a matter of convenience. Time zones are even used in space. The International Space Station follows GMT (Greenwich Mean Time), which is 5 hours ahead of ET in the U.S.
During the warmer months, most countries observe Daylight Saving Time, pushing the clock forward an hour to take advantage of additional sunlight. In Florida, where I live, we switch from Eastern Standard Time to Eastern Daylight Time in the spring.
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