**Thirty days have September,**

**April, June, and November;**

**Thirty-one the others date,**

**Except in February, twenty-eight;**

**But in leap year we assign**

**February, twenty-nine.**

A day is one rotation of the Earth on its axis. A year is the number of days it takes for the Earth to orbit the sun. The problem is that the Earth doesn’t orbit the sun in an even number of days. In fact, it actually takes Earth 365 days, 5 hours, 48 minutes and 46 seconds to complete its orbit (about 365 1/4 days)!

Those extra hours add up so that after four years the calendar is out of step by one day. Adding a day every four years allows the calendar to match up to the solar year again. If we didn’t have leap days and leap years, eventually our months would shift to different seasons.

So, what do we do with all of those 1/4 days? We add a day in a leap year! The extra day is added to the end of February. It becomes February 29. It’s called leap day!

In 1582, Pope Gregory XIII introduced the Gregorian calendar. This is the version of the calendar we use today. This calendar helped solve the problem of the shifting calendar. This is how it works:

- Every year that can be evenly divided by 4 is a leap year, EXCEPT:
- Years that can be evenly divided by 100 (centuries) are not leap years, BUT
- Years that can be divided by 400 are leap years.

Try It! This year is 2016! 2016 ÷ 4 = __. 2016 is evenly divided by 4 , therefore it is a leap year.

What about next year? 2017 ÷ 4 =__. 2017 will not be a leap year because it isn’t evenly divisible by 4.

Will the year 2100 will not be a leap year? Why or why not?

*It’s My Birthday Finally! A Leap Year Story* by Michelle Whitaker Winfrey

It’s My Birthday… Finally! A Leap Year Story A story about a boy named Miles who born on February 29. On Saturday, Miles will be celebrating his birthday. Even though he’s happy there seems to be some confusion about exactly how old Miles will be! Will he be eight or will be be just two?

Post all or one of the activities to your blog and have students respons:

- February 2016 gives you an extra day. Find four things in the newspaper that you would like to do on your extra day.
- Using a newspaper find any numbers, page numbers, sizes, headlines, prices, that are divisible evenly by 4.
- The names of the months on the calendar come from different sources. Research the names of the months and the names of the days of the week. How many different cultures are involved in our calendar?
- If you were born on February 29th, you’d be called a leapling or a leaper! How would you plan your birthday party?