Why Do We Have Leap Year?
Our oldest son is in kindergarten and is always full of questions regarding the holidays and why we have certain things on our calendar. This week the topic has been leap year. He couldn’t quite understand why every four years, February has an extra day. He’s not one for simple answers, so we did some research to explain it better. This was what we came up with.
A leap year (or intercalary year) is a year containing one or more extra days (or, in case of lunisolar calendars, an extra month) in order to keep the calendar year synchronised with the astronomical or seasonal year. For example, February would have 29 days in a leap year instead of the usual 28. Seasons and astronomical events do not repeat at an exact number of full days, so a calendar which had the same number of days in each year would over time drift with respect to the event it was supposed to track. By occasionally inserting (or intercalating) an additional day or month into the year, the drift can be corrected. A year which is not a leap year is called a common year. The Gregorian calendar, the current standard calendar in most of the world, most years that are divisible by 4 are leap years. In a leap year, the month of February has 29 days instead of 28. Adding an extra day to the calendar every four years compensates for the fact that a solar year is almost 6 hours longer than 365 days. The calendar we use, only requires an extra day once every four years. Other calendars, used elsewhere, do indeed have an extra month every few years.
We had a fun time finding out the scientific reasons for our extra day. He loves learning about science and now he says he wishes his birthday was on the 29th of February, for fun! Take a few moments, and talk to your kids about our special extra day this week!
