Daylight saving time (DST) ends Sunday. We have all been told this means that we save energy and get an extra hour of sleep, but how does this work? Why exactly do we "spring forward" and "fall back?"

When is DST?

Daylight saving time began on Sunday, March 10, when most of America sprang forward by changing setting their clocks an hour ahead. Daylight saving time ends on Sunday, November 3 at 2 a.m.

Be sure not to forget about the clock change; according to a survey by Rasmussen Reports, 27 percent of people admit they have messed up an appointment due to daylight saving time.

History of DST

Daylight saving time was first introduced in Ben Franklin's proverb, "early to bed and early to rise." Franklin's wisdom came while he was in Paris serving as U.S. ambassador. Upon being awoken at 6 a.m., he noticed how much earlier the sun rises than the rest of the world and the possibilities of saving midnight oil.

Daylight saving time became a reality during World War I. Germany was the first to turn their clocks forward in order to minimize the need for coal that powers lights. In 1918, the U.S. standardized an annual start and end to daylight saving time for the states and territories that wanted to participate. From Feb. 1949 - Sept. 1945, daylight saving time became mandatory in order to save materials for World War II.

Does DST really save energy?

According to National Geographic, sometimes less energy is saved because people return to their homes later in the day when it is hotter, which means air conditioning. On the other hand, a 2008 report to Congress said that dayloight saving time saved 1.3 terrawatt hours of electricity and reduces annual national energy consumption by .02 percent.

"The North might be a slight winner because the North doesn't have as much air conditioning, but the South is a definite loser in terms of energy consumption," Hendrik Wolf, an environmental economist, said. "The South has more energy consumption under daylight saving."

Who else follows DST?

Not all U.S. states or territories observe daylight saving time because the federal government does not require it. Those who live in Arizona, except residents of the Navajo Indian Reservation, Hawaii, Puerto Rico, American Samoa, Guam, Northern Marianas, Puerto Rico and Virgin Islands will not fall back by turning their clocks one hour backward.

Russia and Japan do not observe day light saving time. Only some parts of Brazil observe the clock change, including Brasilia, Sao Paula and Rio de Janeiro.

Americans like to use daylight saving time to get a little more active.

"In a nationwide American time-use study, we're clearly seeing that, at the time of daylight saving time extension in the spring, television watching is substantially reduced, and outdoor behaviors like jogging, walking, or going to the park are substantially increased," Wolff said.