hmm. Well aren't time zones decided by every 15º of longitude? Or is it 45? I can't remember But - many places of the U.S. (ie: Maine) are in a completely different time zone, but to keep things simple and not split up and isolate certain areas sometimes the time zones go around entire states, cities, etc.
I'm not sure, but you're probably right. And since Indiana and Illinois border the two time zones that's probably why the difference it more noticeable. Perhaps half of Illinois or half of Indiana should actually be in the other time zone. The part of Indiana I grew up in was on the western border, so perhaps we should have been in the central time zone in reality if it were based strictly on longitude.
I think there are primarily two reasons for DST - economic and political. You'll note from your map that equatorial regions have the lowest incidence of DST, mostly because the daylight hours do not change dramatically between the seasons. These are also the developing regions, so their power requirements are not the same as those at higher latitudes
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Haha, yeah I understand completely what you mean. People that have always been used to changing their clocks and observing a specific time zone never think about the difference between DST and ST. Growing up in Indiana, I completely understand the concept though. Sadly, the new youth of Indiana will be lost on the concept now. It's all up to Arizona now. People outside the state would always ask, "So what time zone are you observing now, Central or Eastern?" The true answer was Eastern, but it was just easier to say Central.
I work with engineers in China and now that we're going to DST and they're not, the difference will only be 13 hours now vs. the 14 during ST in the winter. I'm not sure yet whether this will be a good thing or not.
The not-switching works out better in my case with clients in China, Taiwan, Singapore and India, since they don't observe DST - so once we know the time difference, it stays that way, no matter what the rest of the world is doing.
It also helps that they think of themselves in terms of GMT, so if I say GMT-7, they know what that means. :-)
The problem of where to shift the time zone lines is arbitrary; it's a choice of what clock time to assign to a particular sun position. No matter where you put them, the contiguous locations on either side of the line are going to have clock-to-sun discontinuities.
The choice of size of time zones is more interesting. It's a trade-off between the size of the error in sun-to-clock assignment and the hassle of having to deal with different times. On the one extreme, the whole country/world could be in the same zone but the sun would set at drastically different times, and on the other, every single longitude could have its own clock setting and the sun would set at the same time.
Re: Discontinuityengineerboi81March 11 2007, 20:24:17 UTC
I can see your point. Like mentioned by someone else, it's often a combination of economic and political issues that creates the need for time zones and the observance of DST. The sun doesn't actually set, since it's in a fixed position. So each longitude has a different perception of when the Sun actually sets due to our rotation. So it's really part of our perception that the Sun should set in the evening that we cater to by defining time zones. Then due to our orbit around the sun we try to extend the daylight hours by using DST during the summer part of our orbit around the Sun. However, this just doesn't work for those regions of the globe that are far north or south due to our tilted axis. What a mess... LOL
I was always taught that daylight savings time was an economic thing. basically the shift in the time just means that instead of getting light really early when no one is really up we move the clocks so it stays dark and extra hour and gets late an extra hour. the whole point is that this way people can utilize daylight instead of electric light. this in turn lowers electric bills and also frees up electric use for other consumption. a recent innovention that is a perfect example is air conditioning. instead of using the lights the electricity can be rerouted to a/c to prevetn system wide overuse and failure. also daylight at 10P.M. may seem weird but in the summer when it is hot out people tend to go to bed later and therefore use the daylight rather than loose it to the morning
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I work with engineers in China and now that we're going to DST and they're not, the difference will only be 13 hours now vs. the 14 during ST in the winter. I'm not sure yet whether this will be a good thing or not.
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It also helps that they think of themselves in terms of GMT, so if I say GMT-7, they know what that means. :-)
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The choice of size of time zones is more interesting. It's a trade-off between the size of the error in sun-to-clock assignment and the hassle of having to deal with different times. On the one extreme, the whole country/world could be in the same zone but the sun would set at drastically different times, and on the other, every single longitude could have its own clock setting and the sun would set at the same time.
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