Have you ever wondered why we have leap years? It’s a really interesting question! Normally, February has 28 days, but every four years, we add an extra day, making it 29 days. This extra day is called February 29th, and the year is known as a leap year. But why do we do this?
Imagine being born on February 29th. Does that mean you only get to celebrate your birthday every four years? That would be quite unusual! Some people born on this day might say they’re 11, 12, or even 7 years old, even though they’ve been around much longer. So, why do we add this extra day?
To understand leap years, we need to know a bit about our calendar. The calendar we use today was created a long time ago. It has 365 days in a year because that’s roughly how long it takes for the Earth to travel around the sun. This journey also takes us through the four seasons: winter, spring, summer, and fall.
But here’s the catch: the Earth doesn’t take exactly 365 days to orbit the sun. It’s actually about 365 days and 6 hours. Those extra 6 hours might not seem like much, but over time, they add up. If we ignored them, our seasons would start to shift. Imagine winter in August or summer in December!
To fix this, ancient astronomers came up with a clever idea. Instead of adding a 6-hour day each year, which would be strange, they decided to save up those hours. After four years, those extra hours add up to a whole day. So, every four years, we add an extra day to the calendar, and everything stays in sync. This is why we have leap years!
Thanks to leap years, our calendar stays aligned with the Earth’s journey around the sun. This way, the seasons happen when they’re supposed to, and everything stays in order. It’s a smart solution that keeps our calendar working just right.
That’s the story of leap years! It’s amazing how a little extra time can make such a big difference. Keep asking questions and stay curious about the world around you. There are always more mysteries to explore!
Leap Year Birthday Celebration: Imagine you have a friend who was born on February 29th. Plan a special birthday party for them that happens every four years. Think about how you would make it extra special since they don’t get to celebrate on their actual birthday every year. Draw a picture of the party and write a short story about what makes it unique.
Earth’s Journey Around the Sun: Create a simple model to understand how the Earth orbits the sun. Use a flashlight to represent the sun and a small ball to represent the Earth. Move the ball around the flashlight to see how the Earth travels in a circle. Notice how it takes a little more than 365 days to complete one journey. Discuss with a friend or family member why adding an extra day every four years helps keep our seasons in the right place.
Leap Year Detective: Become a leap year detective and find out which years are leap years. Look at a calendar and find the years that have February 29th. Can you find a pattern? Try to predict the next leap year and explain why it will have an extra day. Share your findings with your class or family.
Sure! Here’s a sanitized version of the transcript:
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(telephone ringing) – Hi, Doug. – Hi, Sire. – I have a question for you. Why do we have leap years? – Ooh, that’s a great question. The month of February always has 28 days. Except every four years, we add one more day at the end, a February 29th. In other words, we add an extra day to our whole year. When this happens, this is what we call a leap year. Why do we do this?
Think about how unusual it is if it’s a leap year and you were born on February 29th. Would that mean you don’t get to have your first birthday until you’re four years old? And that when all your friends are eight years old, you’re technically only two years old?
These individuals were all born on February 29th. Listen to them describe their age. – I’m Cherie and I’m 11. – I’m Genevieve and I’m 12. – And I’m Brianna and I’m going to be seven. – [Doug] Why do we do this? Why do we add an extra day to our calendar once every four years? What ideas do you have? If you want to stop and think about it, now would be a good time to pause the video.
Okay, you ready? So why do we add a day to our calendar every four years? Well, first you have to know something about our calendar. This calendar that we use today was invented a long time ago. You might even know that our one-year calendar contains 365 days. That’s not just some random number that these ancient calendar inventors made up. They chose that number on purpose because it’s the number of days it takes for the Earth to go around the sun.
Or another way of looking at that, 365 days is the number of days it takes for the Earth to go through all four seasons: winter, spring, summer, fall. These inventors of the calendar wanted the calendar to match what the Earth is actually doing. And 365 is the number of days in a year.
But wait a second, because these same ancient inventors of the 365-day calendar that we use today are also the people who created the idea of a leap year, the idea of adding an entire day to our calendar once every four years. Why would they do that? That almost seems like a bad idea when you stop and think about it. I mean, if you want your calendar to match up nicely with the seasons, don’t add an extra day. It’s not like the Earth has an extra day in its orbit around the sun every four years.
So why do we do this then? Well, the easiest way to answer this might be for us to imagine that you and your friends could travel back in time and stop the ancient inventors of the calendar from ever starting the idea of leap years to begin with. Let’s imagine you did that. You and your friends go back in time, find the people who invented our calendar, and convince them not to add February 29th. You say, “We’re smart. We’re from the future, trust us. Let’s just keep the calendar simple. Keep it at 365 days each year, always.”
Then you get in your time machine and you come back to the present. But guess what? As soon as you come back, you’d soon find out that you and your friends really messed something up with our calendar. Because now, winter is happening in the middle of August. Summer is happening in the middle of December. Now, whatever season your birthday was in, it’s the opposite season.
Oh no. What have you done? At this point, you and your friends decide to go find an expert who studies how the Earth moves around the sun, an astronomer. You ask them, “What did we screw up?” They tell you, “Well, actually, we found out a long time ago that the Earth doesn’t go around the sun in 365 days.”
Wait, what? It doesn’t? Well, it’s just not exactly 365 days. 365 is just a close number. You see, when ancient astronomers studied the sky very carefully, they were able to figure out that one year isn’t quite 365 days. It’s not 366 days either. It’s somewhere in between that. In fact, it’s about 365 days plus six hours.
A year isn’t perfectly 365 days? There’s an extra six hours? What do you do with that on a calendar? This is a tricky problem. If you completely ignore the extra six hours, you don’t even worry about putting them on your calendar, well, that’s no good. Because even though it is just a little bit of time, as each year goes by, those extra six hours keep adding up. Eventually, after a few hundred years, the months on your calendar won’t be connected to the right seasons anymore.
That’s what happened in that time machine scenario. One of your friends has an idea. “What if every year we add a day to the calendar but it’s a day that’s only six hours long?” That is one way to solve this problem. Now the calendar will match how long the Earth actually takes to go around the sun each year.
It’s a little bit of a weird way to solve it, though. Think about it? A day that’s only six hours long? You’d be sleeping, then wake up, eat your breakfast, then get your teeth brushed, and it’d be like, “Oh, six hours is almost over. It’s almost March 1st now.” Time for bed again, I guess? Most people probably don’t want a weird six-hour day on their calendar.
Another friend has a different idea for how to solve this. “What if instead of adding a six-hour day to the calendar, and instead of ignoring the six hours altogether, we just ignore the six hours for a few years? We save them up. Then once every few years, we can just add an entire day and it will all even out.”
Now, that’s a pretty great idea. And you know how many years you should wait before you add an entire day? Well, if you wait every four years, that adds up to one entire day. That’s what a leap year is. And that is why the ancient people who invented this calendar decided a long time ago to make sure we add an extra day once every four years so that the calendar we’re using always stays lined up with how long it takes for the Earth to go around the sun.
That’s all for this week’s question. Thanks, Sire, for asking it. Now for the next episode, I reached into my question jar and picked out three questions sent into me that I’m thinking about answering next. When this video is done playing, you’ll get to vote on one. You can choose from, “Why are lemons so sour?” “How does cotton get turned into clothing?” or “Why do we have tears when we cry?” So submit your vote when the video is over. I want to hear from all of you watching. There are mysteries all around us. Stay curious and see you next week.
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