Because we had one single time zone for Earth, noon would be the middle of the day in some places, but it would be morning, evening and the middle of the night in others.Since different parts of the Earth enter and exit daylight at different times, we need different time zones.Each time zone is 15 degrees of longitude wide.
Not always 1 hour's difference. Some countries have non-standard time zones, usually with a 30-minute offset (a few have a 45-minute offset). For example, the time zone in India is five hours and 30 minutes (UTC+5:30) ahead of UTC. Time zones’ boundaries are irregular mainly because of political factors, and so this has been a subject of criticism. How Time Zones Work. Each time zone is then theoretically 15 degrees wide, corresponding to a one-hour difference in mean solar time. The shape of time zones is changed, in practice, to match internal and international borders. Report Abuse. We have time zones so that everyone on the planet does most things at the same time that a person does in another part of the world such as sleeping for example. The majority of people sleep at night. The reason there are different time zones and an International dateline is because there are different times. I suppose we could all go on GMT but that would mean that when it is 12:00 GMT it would be the middle of the night in Tokyo and early morning in New York. World Time Zones. Here are the time zones of the world. All places in one time zone have the same time, except when a region has Daylight Saving Time when the local time is advanced by one hour. On this map there is no adjustment for Daylight Saving Time! (Note: the clock uses the time on your computer as its reference). The concept of having a time zone comes from a basic desire to always have the local time correspond to the amount of daylight that is available. Most people tend to think of the middle of the day, or high noon, as being the time at which the sun is at the highest point in the sky. Time zones ensure that the sun appears at its zenith in every part of the world. A global map, including time zone divisions. There are 24 different divisions of time zones around Today’s Time Zones. The definition for time zones can be written in short form as UTC± n (or GMT± n), where n is the offset in hours. There are also some places that have UTC+13 and UTC+14 but these are not standard time zones, from a point of view that sees the number of standard time zones as 24. How Time Zones Work. Each time zone is then theoretically 15 degrees wide, corresponding to a one-hour difference in mean solar time. The shape of time zones is changed, in practice, to match internal and international borders. Best Answer: The concept of having a time zone comes from a basic desire to always have the local time correspond to the amount of daylight that is available. In short, most people tend to think of the middle of the day, or high noon, as being the time in which the sun is at the highest point in the sky. The reason there are different time zones and an International dateline is because there are different times. I suppose we could all go on GMT but that would mean that when it is 12:00 GMT it would be the middle of the night in Tokyo and early morning in New York. In order to build the time zone map, they studied Earth’s movements. As the Earth rotates on its axis, it moves about 15 degrees every 60 minutes. After 24 hours, it has completed a full circle rotation of 360 degrees. The scientists used this information to divide the planet into 24 sections or time zones. Each time zone is 15 degrees of longitude wide. If we had one single time zone for Earth, noon would be the middle of the day in some places, but it would be morning, evening and the middle of the night in others. Since different parts of the Earth enter and exit daylight at different times, we need different time zones Time zones are based on the fact that the Earth moves 15 degrees longitude each hour. Since there are 24 hours in a day there are 24 standard time zones. (24 hours x 15º=360º). Time zones are counted from the Prime Meridian (0º longitude). Each time zone is counted at 15 º intervals and extends 7½º either side of a central meridian.  Each time zone is 15 degrees of longitude wide (with local variations) and the local time is one hour earlier than the zone immediately to the east on the map. The number of standard time zones is debatable and discussed among various sources, particularly with regards to the International Date Line. How Time Zones Work. Each time zone is then theoretically 15 degrees wide, corresponding to a one-hour difference in mean solar time. The shape of time zones is changed, in practice, to match internal and international borders.
http://www.timeanddate.com/time/time-zones.html https://answers.yahoo.com/question/index?qid=20090103082203AAyuc5Y http://www.mathsisfun.com/time-zones-world.html http://www.wisegeek.org/why-are-there-different-time-zones.htm http://www.timeanddate.com/time/time-zones.html https://answers.yahoo.com/question/index?qid=20090103082203AAyuc5Y http://wonderopolis.org/wonder/why-do-we-have-different-time-zones/ http://www.youtube.com/watch?v=X1DkiuaFCuA http://www.timeanddate.com/time/time-zones.html
why do we have different time zones