Leap year is something we only have to address every four years, but it plays an important role in keeping us on time with the universe. Explaining why we have leap year can be difficult, especially if you have younger children in your care. You'll likely want to keep your explanation short and simple for them, but you can give older students a more in-depth explanation.
It's All Due to an Out-of-Sync Calendar
Our calendar is based on how long it takes Earth to orbit the Sun. We have 365 days in a regular calendar year, but it actually takes a little longer than that for Earth to do a full orbit around the Sun. Since our calendar doesn't account for that extra time in the solar year, we have to add a day to the calendar every four years to ensure that our calendar is in sync with the seasons.
The Julian calendar (named for Julius Caesar) was one of the first calendars to account for a longer solar year. However, adding a leap day every four years resulted in a surplus of time, once again making the calendar out of sync with the solar calendar. Pope Gregory XIII addressed this issue in 1582 when he instituted the Gregorian calendar, which is the calendar the majority of the world uses today.
Did You Know?
The Gregorian calendar still adds a leap day every four years, but there is an exception to that rule. If a leap year is evenly divisible by 100 but not evenly divisible by 400 (e.g., the years 1700, 1900, and 2100), then that leap year is skipped to account for the surplus of minutes caused by adding a leap day every four years.
Incorporating Leap Year into Your Lesson Plans
Now that you know more about why we have leap year, here are a few ideas on how you can incorporate lessons about leap year into the classroom:
- Have students do their own research on why we have leap year.
- Come up with a special Leap Day project for students.
- Emphasize the number 29 in a math activity or writing prompt.
- Teach children about creatures that leap, such as frogs and kangaroos.
- Use Leap Day as an opportunity to teach children calendar and time skills.
- Make a table and graph of how far everyone can leap or jump.
Browse the Time and Calendars category of our Math section for a variety of materials you can use to build children's time-telling skills and knowledge about calendars.
Sources:
Andrews, Evan. "Why do we have leap year?" History. A+E Networks. 19 Feb. 2014. Web. 11 Feb. 2016.
Shepherd, Marshall. "2016 Is a Leap Year. Why Do We Have Them?" Forbes. Forbes. 4 Jan. 2016. Web. 11 Feb. 2016.