Spring forward, fall back, what’s it all about? This weekend daylight-saving time kicks our clocks forward an hour, waking us up an hour earlier and giving us an extra hour of sunshine at the end of our day all summer long.

Who came up with this idea?

One of America’s founding fathers and great thinkers, Benjamin Franklin, came up with the idea in 1784. He wrote an essay called “An Economical Project,” where he pointed out that rolling the clocks forward an hour in the summer would save on lamp oil because people would have an extra hour of sunlight in the evenings, then go to bed pretty much when it got dark.

In 1966, Congress passed the Uniform Time Act, mandating that daylight-saving time begin the last Sunday of April and end the last Sunday of October. Any state that wanted to be exempt needed to pass a state law.

In 1986, Congress changed the law to start daylight-saving time the first Sunday of April and end the last Sunday of October.

Why do we do it?

It still saves energy and fuel. After the 1973 Middle East oil embargo, the United States stretched daylight-saving time for several more months in 1974 and 1975 and saved 10,000 barrels of oil each day.

Because of the time change, people drive home during daylight, which saves lives because the drivers can see other cars and pedestrians better. It also helps reduce crime, because people can do their errands after work in the daylight and reduce exposure to criminal activity that typically occurs at night.

Does everybody go on daylight-saving time?

In the United States, three states have voted not to switch time: Arizona, Hawaii and Indiana.

Time in Indiana, which falls into two different time zones (Eastern and Central), is really complex. Seventy-six counties in the Eastern time zone do not change time at all, 11 counties near Chicago in the Central time zone do change to daylight-saving time and five counties (a couple near Cincinnati, and three near Louisville) in the Eastern time zone also switch. Got that?