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The Sciences

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Why Do We Have Daylight Savings Time?


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"Why do we have daylight saving time?"

Eileen Burke, Boston, Massachusetts

David Prerau, author of Seize the Daylight (, replies: Moving the clock forward in the spring shifts an hour of sunlight from morning to evening, providing more usable hours of daylight. The concept goes back to Benjamin Franklin, who in 1784 recognized that by rising earlier, people could light their homes for more of the day with sunlight rather than expensive candlelight. In 1905 Englishman William Willett came up with the revolutionary idea of moving the clocks forward to make better use of daylight hours. The plan was adopted by the combating nations of World War I to save energy. Today 70 nations encompassing well over a billion people observe daylight saving time. Proponents note that advancing the clock saves energy, reduces automobile accidents, promotes outdoor activities, and cuts crime. But daylight saving time also has its detractors, ranging from parents who worry about their children's trips to school on dark mornings to farmers whose tasks depend on the sun and whose daily schedules are pushed back an hour behind everyone else's. Starting next year the United States will extend daylight saving time by an additional month—from the second Sunday in March to the first Sunday in November—but any state may opt out, as Arizona and Hawaii do.

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