How Daylight Saving Time works
By Marshall Brain
http://www.JewishWorldReview.com | (MCT) Every spring and every fall we go through a funny little dance as a society. It's called Daylight Saving Time, or DST, and it has all of us setting our clocks forward and backward. Some people like DST, some people hate it, but we all get to participate in the dance.
This year the dance is a little different. A law called the Energy Policy Act of 2005 has changed the dates for DST to start and end. This change is adding a bit of extra intrigue to a process that is already something of a nuisance.
Therefore, you might be wondering - why do we do this? Where did the idea of Daylight Saving Time come from?
Let's start by going back to the 1800s. There really wasn't any sort of national time standard in the United States. Each town or city used some local landmark to set its local time. For example, a church in the center of town might have a tall steeple clock that rang a bell every day at noon. Everyone in town would set their watches by that clock. That clock would set its time based on the sun - when the sun reached its highest point during the day, that would be noon.
This system of local time all changed in the 1883. The railroads needed a standard way to think about train schedules across the United States. So they created the first time zones as well as a standard time system. The worldwide system of time zones, with Greenwich Mean Time as the zero hour, came into play in 1884. Cities and towns all aligned themselves with the train's time system because, if they did not, people would miss the train.
The move toward Daylight Saving Time started as early as Benjamin Franklin, but did not become a national law in the United States until World War I. In 1918, congress passed the law that created DST. Why? The whole system was designed as a way to save energy.
Here's what happened. If you think about how the days lengthen in the spring, you realize that the sun is coming up earlier and earlier. Eventually, if you don't have a DST program in place, the sun is coming up at 5 a.m. or earlier. Most people do not wake up at 5 a.m., so that hour or two of morning sunlight is "wasted" on people who are asleep in bed.
The idea behind DST is to move an hour of "wasted" sunlight to the other end of the day, when people are actually awake. Because of the extra hour of sunlight in the evening, people don't have to turn their lights on, and that saves electricity. The savings are not gigantic - maybe only 1 percent or 2 percent of a country's total electrical consumption is saved. But in a country as big as the United States, a 1 percent reduction in electricity consumption is a lot of electricity.
For the last several decades, DST has started on the first Sunday in April. The Energy Policy act of 2005 changes the start date to the second Sunday in March. The goal is to save a little more electricity, although the jury is still out on whether the new law will have much of an effect.
The bigger question is, how disruptive will the new DST dates be? If it weren't for computers, this change would not really be disruptive at all. People would simply set their clocks by hand and it wouldn't matter. Many computers, however, were programmed with the thought that DST would always start on the first Sunday in April. Now that things are changing, the code for these computers has to change. On older systems (and older pieces of equipment like VCRs), change may not be possible. Adjusting things by hand will be the only option.
So, is DST worth all of this hassle? Perhaps. The energy savings are measurable and undeniable. But it is also the case that people seem to like the DST system. When pollsters do surveys, Americans tend to agree with the idea of long, late summer evenings, rather than having the sun in their eyes while lying in bed at 5 a.m. That, agreement, ultimately, may be the thing that gives DST its appeal.
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