Up until now, I thought it was daylight savings time, not daylight saving time.

And this is mental floss on YouTube today.

I'm gonna answer Jerome's big question.

Why does daylight saving time vary by country?

Still sounds.

Let's get started.

Country started using daylight savings time or D S T or dissed during World War to clarify any time I say d S t in this video, I'm referring to setting the clocks ahead in the summertime.

So the sun is out longer during the evening hours, then returning to what's known as standard time during the autumn.

Germany was the first country to do this.

The implement that it in order to save energy, the British adopted it shortly after than most of the other countries in the war did to in the US observing D S t was a federal law for both of the world wars, but after World War two, it became a decision of the state.

Currently, the majority of countries in North America and Europe observe daylight saving time.

Most countries in Asia and Africa don't only about 70 countries or 1/4 of the world's population observant, but a lot of countries have flip flopped on D S T over the years and probably will continue to.

This is for a couple reasons.

Some people believe that it saves energy.

Some say that it's bad for health, and some think it's just an inconvenience.

There's no clear consensus on whether daylight saving time actually saves energy.

In 2008 the National Bureau of Economic Research, or neighbor, found that even though people used less light during D.

S.

T, they use their air conditioning Maur.

So there was actually an increase in energy hoagies.

U.

S Department of Energy, on the other hand, claims that 0.2% less energy is used annually.

Thanks to D S T.

Experts also don't agree on whether it's a health issue.

Come on, experts.

Can we all get along?

Can do some research.

Your experts find out if we can.

Some studies show that our bodies never adjust to D.

S t, and it increases the risk of illness.

Others say that an extra hour of sunlight encourages people to be healthy and exercise more.

That said, I can't go through and tell you why each country does or doesn't observe D S t because I might own daylight is limited and I have to save it.

But I can give you some examples.

In 2011 Russia declared that it would stay India's two year round, but people hated it because of the dark winter, so they switched to standard time.

Some predominantly Muslim countries like Morocco don't use d S t during Ramadan because people fast during daylight, so they prefer the sun goes down earlier.

Others just avoid d S t all together in the U.

S to states regularly.

Don't observe D S t Arizona and Hawaii Arizona because they're a bunch of jerks.

Why?

Because they're an island off in the middle of nowhere?

No Arizona.

You're probably great.

You haven't observed it since the sixties.

Officials believe that they're saving energy by not having an extra hour of sunlight time that people would likely spend running their air conditioning.

And a wise latitude makes it so that D S t wouldn't affect them that much.

They get basically the same amount of daylight, no matter what season.

And the weather is perfect all year round of you been?

No.

Why?

It's amazing.

Thanks for watching mental floss on YouTube, made with the help of all of these nice day light sabers.

If you have a big question of your only, like answered, leaving below in the comments, See you next week.