Daylight saving time (DST), also summer time in British English, is the convention of advancing clocks so that afternoons have more daylight and mornings have less. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn; the ancients lengthened summer hours instead. Presaged by a 1784 satire, modern DST was first proposed in 1907 by William Willett, and 1916 saw its first widespread use as a wartime measure aimed at conserving coal. Many countries have used it since then; details vary by location and change occasionally. Adding daylight to afternoons benefits retailing, sports, and other activities that exploit sunlight after working hours, but causes problems for farmers and other workers whose hours depend on the sun. The extra afternoon daylight also cuts overall traffic fatalities; its effect on health and crime is less clear. DST can save electricity by reducing the need for artificial evening lighting, but it can also boomerang by boosting peak demand, increasing overall electricity costs. DST's clock shifts complicate timekeeping and can disrupt meetings, travel, billing, medical devices, and heavy equipment. Many computer-based systems can adjust their clocks automatically, but this can be limited and error-prone, particularly when DST rules change. The clock shifts also can serve as twice-yearly reminders to replace smoke alarm batteries and review fire escape plans.
Wikipedia
Day Light Saving Time
E-Cards - Send Day Light Saving Time Greeting Card!
Send An E-Card For
Any Occasion
flashgreetingscards.com 2006 ©
All Rights Reserved free greeting cards Free
eCards
|
|
|
|
