Why do we have Daylight Saving Time?
24 min
•Mar 3, 20263 months agoSummary
This episode of Brains On! explains why Daylight Saving Time exists and how it affects our bodies. The show covers the astronomical reasons for shorter winter days (Earth's tilt), the history of DST starting in World War I to save energy, and the negative health impacts of clock changes on our circadian rhythms.
Insights
- Daylight Saving Time doesn't actually save daylight—it redistributes when we experience it by shifting our daily schedules relative to sunrise/sunset times
- The original energy-saving purpose of DST during WWI no longer applies in modern times, yet the practice persists as habit
- Clock changes disrupt circadian rhythms for several days, causing measurable increases in insomnia, heart problems in older adults, and car accidents
- Farmers historically opposed DST because it forced them to work in darkness during early morning chores while city workers benefited from evening light
- Geographic location matters significantly—regions near the equator experience minimal daylight variation, while far northern/southern areas see extreme seasonal differences
Trends
Growing scientific evidence questioning the health benefits of Daylight Saving Time practicesRegional resistance to DST adoption—multiple U.S. states and territories opt out of the practiceIncreased public awareness of circadian rhythm disruption and its physiological consequencesHistorical policy decisions (like candy industry lobbying to extend DST for Halloween) influencing modern practicesEducational content targeting children to build scientific literacy around time, astronomy, and health
Topics
Daylight Saving Time history and implementationEarth's axial tilt and seasonal daylight variationCircadian rhythm disruption and sleep scienceEnergy consumption and policy effectivenessHealth impacts of clock changesWorld War I energy conservation measuresRegional time zone variationsAstronomical seasons and planetary mechanicsAgricultural vs. urban scheduling conflictsHalloween candy industry influence on policy
Companies
KitchenAid
Listener Uzum from KitchenAid submitted the episode's main question about why Daylight Saving Time exists.
People
Molly Bloom
Host of Brains On! who guides the episode discussion and interviews co-host Ava about Daylight Saving Time.
Ava
Co-host from Minneapolis who participates in the episode discussion and shares personal perspectives on time changes.
Quotes
"You can't actually save daylight. Like put it in a jar and keep it for later or store it in the sun bank?"
Molly Bloom•Early episode
"The farmer objects to doing his early chores in the dark merely so that his city brother, who is sound asleep at the time, may enjoy a daylight motor ride at eight in the evening."
Historical magazine letter writer (quoted)•Clock facts section
"Daylight saving is low-key terrible for our health."
Dwayne the Brain•Health impacts segment
"Moving the clocks can mess with our internal body clocks called our circadian rhythm. But the effects wear off after a week or two."
Molly Bloom•Episode summary
Full Transcript
Friends, we are so super duper excited to tell you that we just added a bunch more cities to our 2026 live show tour. Get ready for singing, dancing, magic tricks, game shows, mystery sounds and scientists falling from the sky in a totally safe way. We promise. Plus, there's a chance for you to attend special meet and greet parties in every city. So come on. This spring, we're coming to Milwaukee, St. Paul, Atlanta, Fort Lauderdale, Chattanooga, Durham, San Francisco, Portland, Buffalo, Toronto, and Ann Arbor. We're basically going to be everywhere. Look behind you. Are we there? No? Well, we probably will be soon. Head over to BrainsOn.org slash events for tickets. And make sure you grab passes to our meet and greet party. You get to ask us questions, take pictures with us, and I'll even do some close-up magic. That's BrainsOn.org slash events. Can't wait to see you. Lemonada. Brains On Universe. You're listening to Brains On, where we're serious about being curious. Imagine you had a superpower. You can control time. You can speed up the day or slow it down at will. Maybe you decide to move time backward an hour in the mornings, so you can squeeze in a few more dreams before school. Or you jump an hour forward to skip over your dentist appointment. You'd be pretty powerful. And it's kind of what we do with our clocks twice a year. You know, fall back and spring forward. Those are the times when we jump ahead or backward by one hour, or at least the clock jumps through time, even if we don't. Today, we're going to talk about why we do that. And why it might be tough on our bodies. Stay with us. Hey, Gangador. How's the new job going? Very busy. Being CEO is big job, even for a big monster like Gangador. Yeah, I've noticed that ever since we made you CEO of Brains On Universe, you haven't been at the dance studio as much. Yeah, Gangador misdoing twirls, but some monster need to keep this place running. True. Hey, you listening. Yeah, you can help us and Gangador out. When you join SmartyPass, you support Brains On, Smash Boom Best, Forever Ago, and all the cool things we do. Plus, you'll get an ad-free feed of all our shows, invites to online hangs with us, discounts on shirts and hats, and you can even get a special custom message from Molly. From Gangador! Gangador will shout, happy birthday! Or tell secret to Gangador's leg day workout routine. The secret is jogging through a pool of jello. Much resistance! Go to smartypass.org to sign up. Remember, good things exist when good people support them. So help us keep the lights on and help Gangador get back to what he loves. Sweating and twirling! Yeah! You're listening to Brains On from the Brains On universe. I'm your host, Molly Bloom, and my co-host today is Ava from Minneapolis. Hi, Ava. Hey, Molly. So we're gathered here today to answer this question. Hi, my name is Uzum from KitchenAid, and my question is, why do we have daylight savings time? So daylight saving time is part of the year here in North America when we move the clocks forward an hour. It also happens in lots of other places like Europe, Egypt, and parts of Australia. In fact, it's happening soon. Ava, I'm just wondering, does this change trip you up every year? Not really. I kind of like having longer and shorter days. Yeah, you're like, oh, this is like a fun adventure. Yeah, definitely. So in Minnesota, where we are, would you say it gets dark pretty early in the winter? Yeah, I'd say so, definitely. Yeah. It's always a bummer when it's like 4.30 and I'm like, the sun is down. Yeah, that part's not so great. Yeah. So what do you prefer, getting up early and getting the morning light or staying up late? I like both, but if I'd have to choose, I would say staying up late. Yeah, you're a night owl? Yeah. So if you could choose to jump forward one hour every year, what hour would you like to skip over? I would skip four to five because that's my bus ride and it's really long and it gives me a headache. Oh, okay. So, yeah. That sounds like a really good one to skip. Yeah. Good choice. So, if you could go back one hour, repeat an hour, when would you use that power? I think I would go back an hour at 7 o'clock so I could have more sleep before going to school. Very smart. So, like, one more hour of sleep, please. By the way, you might have noticed we're saying daylight saving and not daylight savings. There's no S. Kind of tricky. I learned that when we started making this episode. But to Uzam's question, why do we have daylight saving time? You'd think based on the name, the idea is to save daylight, but you can't actually save daylight. Like put it in a jar and keep it for later or store it in the sun bank? Yeah, that's not going to work. Nope. You get a certain amount of sunlight each day, no matter what. We're not in control of that. But we are in control of our clocks and our routines. Like when we wake up. When we start and end work or school. And when we go to bed. Good night, Ava. Night, Dad. All would be well and good for our schedules if the sun rose and set at the same time every day. Yeah, but it doesn't work that way. No, sir, it does not. Here in North America, there is more daylight in the summer and less light in the winter We move the clocks forward in the spring so there is more light in the evenings which also means there is less light in the mornings But why are the days so much shorter in the winter anyway Molly Ava I a time traveler from the present here to help answer your question. Hey Sandin, um, why are you wearing that shiny outfit covered in bubble wrap? Yeah, I'm a time traveler from the present. Wait, if you were from the present, doesn't that mean you're From right now? How is that time traveling? And it still doesn't explain the outfit. Are those swim flippers on your feet? Okay, okay. I haven't traveled in time yet, but I plan to very soon. On Daylight Saving Day, I, Sandin Time Traveling Totten, will boldly go one hour into the future. I'm wearing this bubble wrap and tinfoil cardigan with the flipper shoes because my trend forecasts say this is how people will be dressing in the future. You mean one hour into the future? Precisely. Molly, it's going to be like a whole new world, and I need to blend in. Now, I've been studying this miraculous time jump for weeks, so I can help explain anything about it. Actually, we were just wondering. We changed the clocks in late winter to get more light in the evening. But why is there so much less daylight in the winter anyway? Great question. It actually has to do with how our planet tilts. Think of it this way. Imagine our planet is a golf ball. And imagine that golf ball is going in circles around a giant light bulb. That's the sun. Okay, I am imagining it. A golf ball circling a big light. Great, great. Okay, now, not only is the golf ball making a big circle around that light, Imagine that it's also spinning around and around, kind of like how a top spins. So it's making little twirls while it makes one big circle around the light. I'm getting dizzy thinking about it, but okay. Okay, so each time that ball spins around one time like a top, that's one day. Each time it goes all the way around that big light, that's a year. Makes sense. Now, if that ball was facing the light straight on, the amount of daylight would be the same all year. But our Earth is not facing the sun straight on. It's tilted a little. So imagine you took that golf ball and you tilted it a little bit. So the top half was more in the light than the lower half. Okay. That top half would be seeing a lot more sun then, right? Exactly. That's what it's like for us in the northern part of the globe when it's summer. We're on the top half of that golf ball. And we're tilting more towards the sunlight. And our days are long. And I'm guessing the bottom half of the golf ball, the part tilting away from the sun, that's winter? 100% spot on. When it's summer in the northern half of the planet, it's winter in the southern half. But here's the thing. As the Earth circles around the sun, it'll eventually get to the opposite side of that star. The tilt stays the same, but now the southern part is angled to the sun and the northern half is angled away. Oh, so that's winter for us in the north. And summer in the south. Correct. And if you live right along the middle of the planet, like the belt we call the equator, the length of the days doesn't change all that much in the summer or the winter. But when you live really far north or really far south, you can get extremely short days in the winter and very long ones in the summer. So that's why we have short days in the winter. Because right now, our half of the globe is tilted away from the light. And so we aren't getting as much direct sunlight. Wow, thanks for shining a light on that issue for us, Sandin. No problem. Now I have to get ready for our leap forward in time. You should too. Here, eat this. It's a cereal full of riboflavin. I've heard riboflavin helps your body adjust to time travel. I can really taste the riboflavin. them. Enjoy. Now, I'll see you two in the future. No matter what the clock says, I always know when it's time for the... Ava, are you ready for the mystery sound? Yes, I am ready. Okay, here it is. What do you think? I think that that's maybe like a fork or a knife hitting a bowl with some water in it maybe. Like something cleaning it in the sink. Okay. But yeah, I think maybe like a fork like hitting a glass bowl and then also there's some water in it. Okay, so we're hearing a utensil. We're hearing a liquid. We're hearing a bull. Do you want to hear it again? Yes. Okay, here it is again. Thank you. Any new thoughts? Not really. Maybe like two utensils clinking against each other. But honestly, I think I have the same thought. Yeah. Yeah. That sounds very convincing to me. The first thing that popped in my mind was like a spoon and a cup. Yeah. That's what was in my head. So I think you and I are doing a great job. Yeah. All right. So we're going to hear it again, get another chance to guess and hear the answer at the end of the show. Stick around. We've got an episode coming up about baseball. It's a fun sport with lots of fun chants. Like we need a pitcher, not a belly itcher. Nice. But you know what doesn't have great chants? Science. It sure could use some. So make up a fun game day chant for science and share it with us. Ava, can you think of a fun cheer or chant for science? Yeah, so my dad thought of one. Okay, excellent. Thanks, Dad. It's really funny. Okay. Give me a why. Why? Give me a why. Why? Give me a why. Why? If you're so curious, ask a scientist. Bravo I love that one It also encourages arm motions to make a Y wouldn you say I can see a whole stadium doing that I am into it Excellent work Dad So record your cheer or chant and send it to us at BrainsOn.org slash contact. You can also send us drawings, jokes, mystery sounds, or questions. Again, that's BrainsOn.org slash contact. Can't wait to hear from you. Today's episode is sponsored by Bombas. It's the time of the year we think about, hmm, what am I going to do differently this year? Maybe I'm going to read more. Maybe I'm going to work out more. Maybe I'm going to learn a new skill. But really at the top of my list is number one, to get comfy. And that's where Bombas comes in. They're bringing serious comfort to all my everyday go-tos. the all new Bombas sport socks are engineered with sport specific comfort for running golf hiking skiing snowboarding and all sport this year I'm going to walk my dog more longer walks better walks and these socks are going to help me stay comfy while I do it and for all my other resolutions like going to the bookstore and picking out more books to read I'm going to wear my new squishy Saturday suede slip-on shoes which are super comfortable for being on the go Head over to Bombas.com slash Family26 and use code Family26 for 20% off your first purchase. That's B-O-M-B-A-S dot com slash Family26, code Family26 at checkout. This is Brains On. I'm Molly. And I'm Ava. And we're talking about daylight saving. It's something a lot of you are curious about. Hi, my name is Catherine from Richmond Hill, Ontario. And my question is, who invented daylight savings and why do we have daylight savings? Hi, my name is Micah from Queens, New York. My question is, why do we have daylight savings in the USA? So we know that in the winter, days are shorter in the north because our half of the planet is tilted away from the sun. But why do we start moving clocks forward? Turns out, lots of people have suggested changing clocks to make up for shorter days. In fact, in ancient Rome, they just changed the length of the hours to better fit the daylight. So an hour was longer in the summer and shorter in the winter. But moving the clock forward by an hour didn't take hold until much later, during World War I. It was the early 1900s, and there was a big battle across the globe. Lots of countries were fighting. To save energy for the war, some places moved the clocks forward an hour. That way, there would be more daylight in the afternoon and evening. The idea was that people would use less energy-powering homes if they could just rely on daylight instead. The war ended, but daylight saving caught on in the U.S. and was made into law a few decades later in the 1960s. Now, we still switch the clocks forward every spring to get more light after school and work. These days, changing the clock doesn't even save much energy. But we still do it. So there's a lot more to the history of this time change, and we're going to cover it in an episode of Forever Go later this year. But we want to know if you could do anything you wanted with an extra hour of daylight, what would you do? Ava, what would you do with that extra hour of daylight? Well, there's a lot of things I'd want to do, but I think I would want to go over to my friend's house and play on her trampoline for an hour. Nice. It's really fun. That sounds great. That's a perfect use of that hour. So, listeners, send us what you plan to do with your extra hour of evening light. Send it to us at BrainsOn.org slash contact. Thanks. BrainsOn! Okay, time now for some quick clock facts. Quick clock clock fact. You might have heard that one of the reasons we do daylight saving is to make things easier for farmers. But that's not true. Farmers actually were against the time change. They said it really only helps city workers. In fact, one saucy person wrote into a popular magazine to say, The farmer objects to doing his early chores in the dark merely so that his city brother, who is sound asleep at the time, may enjoy a daylight motor ride at eight in the evening. There are some places that don't do daylight saving. Yeah, like China and India. In the U.S., Hawaii, and parts of Arizona don't observe the change either. But the Navajo Nation in Arizona does. Daylight saving used to stop on the last Sunday of October, but candy makers helped get it changed to November. That way, it would still be daylight saving time on Halloween. More daylight equals more time for kids to rake in that sweet Halloween candy. It also means that kids would be safer on the streets since it would be lighter longer. Speaking of clocks, mine says it's time to check the mailbag. We love getting letters, emails, and messages from you all. Okay, oh, here's one. Someone made their own version of our theme song. Let's hear it. hi brainzon i am elliot from greenbrook new jersey and this is the best that i could do of the brainzon theme song nice on a keyboard and everything nice work elliot if you want to play us a song or ask us for some advice, or if you have a joke to share, send it to us at BrainsOn.org contact. Hope to see your name in our next mailbag. BrainsOn is independent, meaning we only exist because people support us. You can get all our episodes without ads and keep us going by joining SmartyPass. Go to SmartyPass.org to sign up and make a difference. Thanks! We a razor Welcome back Ava and I are learning all about daylight saving It doesn actually say daylight but moving the clocks forward makes it so that there more daylight in the evenings Can I just say I utterly detest daylight saving with every single one of my precious neurons? Ugh. Oh hey, it's Dwayne the Brain. A literal brain that can talk. Yes, it's me. I'm her brain and I'm still absolutely wonderful. But I am not looking forward to daylight saving time. Every year it messes me up. Because you get confused about the time? Me too. I can never reset my car clock, so I just leave it wrong until we change time back. True story. Sure. But for me, it's not the time on the clock. It's my circadian rhythm. It gets a wackadoodle. Oh, circadian rhythm. That's like a person's internal clock that tells them when to wake up and when to go to sleep. Exactly. And it's controlled by daylight. When your eyes see the morning rays of sunshine, that internal clock is like, wake up, buddy boy. Time to rise and shine the day away. Right. And when it gets dark, that internal clock tells your body to get tired and sleepy. So you can rest. Yep. So when we jump an hour in the morning, my circadian clock is all like, what the beans? I'm supposed to wake up and now it's too early. Ugh. And when it's evening, my clock is all like, Yo, I'm ready to get cozy in my jammies. Why are we still eating dinner? I feel that too. Waking up the day after the jump is hard. Yeah, bro. Some sleep researchers say insomnia is more common after clock changes. Boo that! And some other scientists have found links between moving the clock and heart problems in older people. And more car accidents too. That makes sense. We're not as sharp when we're groggy. Yeah, daylight saving is low-key terrible for our health. That's why I'm boycotting it, not changing my clock. Maybe I'll leave late to appointments, or early, whatever, I don't care. But scientists also say the effects of daylight saving only last a few days. And in the fall, you get a little extra sleep, which is nice. Also, what kind of appointments does a talking brain even have? Important stuff. You know how Gungador is CEO of Brains On Universe now? Well, I'm Gungador's brain trust. Does that mean you advise Gungador on important business stuff? Nah. I mean, I'm a brain he trusts. So we just tell each other secrets that we'll never share with anyone. Like how Sandin is afraid of green apples. Or how Mark sometimes sneaks off to be the backup catcher for the New York Mets. Top secret stuff. Well, good luck with everything. Thanks for stopping by, Dwayne. Later, broskies! Daylight saving happens in the U.S. when we move clocks forward an hour in the spring. The goal is to get more sunlight in the evening hours, but it also means less light in the morning. It started as a way to save energy during World War I, but it became a normal part of life in certain places like the U.S. Moving the clocks can mess with our internal body clocks called our circadian rhythm. But the effects wear off after a week or two. That's it for this episode of Brainsong. This episode was produced by Molly Blue, Mark Sanchez, and San and Taunton. It was sound designed by Mark Sanchez, who also wrote our theme music. Special thanks to Sam and Jen Rosenbaum, also Ava's sister and the rest of her family, and Ken Taborski at Code of the North for all of their website help. Okay, Ava, you ready to go back to the mystery sound? Yes. All right, let's hear it. Yeah, I think like maybe a spoon scooping or like getting, scooping like maybe water out of a bowl into like another bowl or like the sink maybe. I don't know, something with silverware and a bowl and water. Silverware and a bowl and water. Yeah, that's what I'm thinking. I'm with you. Okay, I'm just going to go out on a limb. I'm going to say spoon. What do you think? Spoon, knife, fork, spoon? We're going spoon. Okay. Okay. Spoon, I'm committing to spoon. Should we hear if we're right? Yeah, spoon or fork maybe. I don't know. Okay. Here is the answer. Hi, Brains On. My name is Kelso. That was the sound of me mixing tea in a teacup with a spoon. Spoon! Yes! Spoon, spoon, spoon, spoon. Okay. We didn't quite get the teacup part. But a teacup is like a tiny bowl. It's a cup. It's a cup. And there's liquid in it. Good job, us. High fives. Now it's time for the Brain's Honor Roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives. Ming Yu from West Windsor, New Jersey. Phoebe and Deacon from Austin, Texas. Henry from Westerfield, Ohio. Eliana from Toronto. Annie from Providence, Rhode Island. Ethan from Birmingham, Alabama. Mason from Australia. Howell from Fairbanks, Alaska. Wesley from Lincolnshire, Illinois. Beckett from Davenport, Iowa. Kai from Toronto. Abigail from Roseville, California. Colin from St. Louis. Aubrey and Noah from Grand Rapids, Michigan. Zandrew from the Philippines, Maggie from Cumming, Georgia, Sally from Gainesville, Georgia, Freddie and Alice from Seattle, Melody from Buena Vista, Colorado, Hadley from Lenoir City, Tennessee, Penny from New Jersey, Logan from Waterloo, Ontario, Charlie, Veda, Parker, Finley, and Callum from Parksville, British Columbia, Nora from Aldi, Virginia, Matan from Chevy Chase, Maryland, Merlin and Mavis from Albuquerque, New Mexico, Jaden from Sanford, Florida, Ezra from Huntington Beach, California, Maddie from Massachusetts, Samuel and Abraham from Chula Vista, California, Henrik from North Carolina, Virgil from Los Angeles, Catherine from from Belmont, Massachusetts, Jojo from Chicago, Harper and Hendrick from Oshkosh, Wisconsin, Sanvi from Prosper, Texas, Martha from Charlotte, North Carolina, Inez from Camden, Maine, Yavani from Leinberg, Germany, Juniper and Genevieve from Bloomington, Indiana, Robin from Swansboro, North Carolina, Aisha and Amrita from San Jose, Costa Rica, Althea from Wakefield, United Kingdom, Emma from Basel, Switzerland, Olin and Solvee from Warren, Minnesota, Kieran from Berkeley, California, Hattie from Westminster, Colorado, Calder and Corley from Silver Spring, Maryland, Tate from Mullen, Nebraska Cameron from Selbyville, Delaware Annabelle from Stansbury Park, Utah Aiden from Cupertino, California Grace from Lexington, South Carolina Elise from Delmar, California Brody from Virginia Alina and Clara from Burke, Virginia Molly from Virginia Luca from Darlington, United Kingdom and Scarlett from Austria We'll be back next week with a mystery sound extravaganza Thanks for listening