Daylight Saving Time is the practice of adjusting clocks so that the optimum amount of daylight is utilized; clocks are turned one hour forward in the spring (spring ahead) and one hour back in the fall (fall behind). It is observed in several parts of the world, most notably North America, with the exception of Arizona, Hawaii, Puerto Rico, and the U.S. Virgin Islands.
What we know today as Daylight Saving Time was an idea originally introduced in 1895 by New Zealand entomologist George Vernon Hudson. He proposed a two hour daylight saving change to the Wellington Philosophical Society which received a lot of interest. Independently, outdoorsman William Willet proposed advancing clocks in the summer months in 1905, which was considered by British Parliament but not officially passed into law.
Germany launched observation of Daylight Saving Time on May 1, 1916 in an effort to conserve fuel during World War I. Many European nations followed suit, and the United States began observing Daylight Saving Time as mandated by the Standard Time Act of 1918. After the war, Daylight Saving Time was eradicated until World War II, when the federal government required states to observe the time change yet again as an endeavor to save energy for war production.
Following World War II, states chose independently whether or not they would adhere to Daylight Saving Time, which took advantage of later daylight hours between April and October. That is, until Congress passed the Uniform Time Act in 1966, legislation that would standardize Daylight Saving Time throughout the nation.
Daylight Saving Time was extended four weeks in 2007 as a result of the Energy Policy Act of 2005. The reason behind this was an attempt to save 10,000 barrels of oil every day, and lengthened Daylight Saving Time from the second Sunday in March to the first Sunday in November.
The benefits of Daylight Saving Time are seen in retail and business, sports, and the decrease in the amount of traffic-related accidents. The time change does present challenges as well, most notably the disruption of travel, billing, record keeping, software updates, and sleeping patterns.