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Why and when the US started changing the clock


Saffeya Ahmed


(CNN)It’s that time of the year again. You wake up and see your kitchen clock reading 8 a.m., even though you swear your alarm was set for 7 a.m. You’re convinced you’re late to work.

But wait, whew.

You’re not late. It’s Daylight Saving Time.

Twice a year, clocks around the world move forward or backward by an hour.
But what’s the point?

There’s an age-old myth that Daylight Saving was a practice adopted to give farmers extra time in the sun to work out in the field. But, that’s not really why dozens of countries follow it.

Daylight Saving Time (DST) is a system to reduce electricity usage by extending daylight hours. For eight months out of the year, the US and dozens of other countries follow DST, and for the remaining four months, revert back to standard time in order to take full advantage of the sunlight.

On the second Sunday of March at 2 a.m., clocks move forward one hour. Then, on the first Sunday of November at 2 a.m., the clocks turn back an hour. A good way to remember it? The time shifts match the seasons: Clocks “spring” forward an hour in March and “fall” back in November.

In the summer months, the sun is out for longer periods of time, so you can *rely on daylight to avoid switching lights on. The clocks revert back to standard time for the winter months so the sun can rise earlier and the world starts the day off with sunlight — otherwise some places wouldn’t see the sun come up until almost 8:30 a.m.


可是等等,你們也沒有遲到。 這是日光節約時間。







When did it start?

The current March-November system the US follows began in 2007, but the concept of “saving daylight” is much older. It’s debated who originally *came up with the idea, but Benjamin Franklin *appeared to have first mentioned it in 1784, when he wrote a letter to the editor of the Journal of Paris.

DST wasn’t widely used until more than a century later, though. Several countries, including Britain and Germany, *implemented DST during World War I. The practice aimed to cut *artificial lighting use so troops could *conserve fuel for the war. But the US didn’t standardize the system until 1966, when it passed the Uniform Time Act.

For years, the US observed DST from the first Sunday of April to the last Sunday of October. In 2005, President George W. Bush extended DST an extra four weeks, officially taking effect in 2007.

But not everyone has opted to follow DST. Only 70 countries around the world “save daylight” every year. In the US, states are not required by law to follow DST — Hawaii and most of Arizona do not observe it. Other states — like Florida and California — are working to observe DST year-round (rather than just between March and November).




這麼多年來,美國從4月的第一個星期日到10月的最後一個星期日都遵守DST。 2005年,布什總統將夏令時延長了四個星期,並於2007年正式生效。


Does DST actually work?

Well … It’s debated.

While the practice can help reduce some energy *consumption, critics have raised concerns of whether the amount of energy saved is worth the *hassle of implementing the system around the world.

In 2008, the US Department of Energy found that the four-week extension of DST from April-October to March-November saved about 0.5 percent in total electricity every day. While that seems like almost nothing, it totals 1.3 billion kilowatt-hours and the DOE says that adds up to “the amount of electricity used by more than 100,000 households for an entire year.”

But a study that same year by the National Bureau of Economic Research concluded that DST increases the demand for electricity — even though lighting usage reduced, demand for heating and cooling increased, so electricity *consumption was about the same.

Other studies have found that benefits of DST may be location-specific. One found electricity reductions in Norway and Sweden, while another saw increased electricity demand in Indiana.

Whether or not “saving daylight” is the most energy efficient method for electricity conservation is still up for debate. But for now, if you live in any of the countries that follow DST, remember to switch your clocks back before you go to sleep Sunday night. Otherwise you’ll wake up thinking you’re late to work.





但是,同年美國國家經濟研究局(National Bureau of Economic Research)進行的一項研究得出的結論是,日光節約時間使電力需求增加了-儘管減少了照明使用,對暖氣和冷氣的需求卻增加了,所以耗電量大致相同。




Implement verb to start using a plan or system 實施
  • The changes to the national health system will be implemented next year. 國民醫療保健制度的改革將於明年實行。
Artificial adjective made by people, often as a copy of something natural人造的,人工的;仿造的
  • artificial fur/sweeteners/flowers 人造毛皮/甜味劑/假花
Conserve verb to keep and protect something from damage, change, or waste 保護;保藏;保存;保留;節約
  • To conserve electricity, we are cutting down on our heating. 為了省電,我們在減少中央供熱。
Consumption noun the amount used or eaten 消費量;消耗量
  • As a nation, our consumption of junk food is horrifying. 我們整個國家對垃圾食品的消費量十分驚人。
Hassle noun (a situation causing) difficulty or trouble 麻煩,困難
  • I can’t face the hassle of moving again. 我受不了再搬一次家的麻煩

Practical Phrases

Rely on to need a particular thing or the help and support of someone or something in order to continue, to work correctly, or to succeed. 依賴;依靠。
  • The success of this project relies on everyone making an effort. 這個專案計劃的成功要靠每個人的努力。
Come up with to suggest or think of an idea or plan 想出,提出(主意或計劃)
  • She’s come up with some amazing scheme to double her income. 她想出一個驚人的計劃來使自己的收入增加一倍。
Appear to To seem like 看起來;好像
  • It appears to me that she isn’t interested in this project, as she hasn’t attended one meeting. 看起來她對這個專案不感興趣,因為她沒有參加任何一次會議。






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