Here are a couple of videos that explain the history of our modern calendar and why we have an extra day every four years. Richard Byrne published them on his Free Technology for Teachers blog a few days ago.
The first video is entitled The History of the Modern Calendar. It is a very quick-paced video with lots of information and name-dropping, so I imagine most readers of this blog will be more than happy to simply understand the general ideas. You can read the transcript for The History of the Modern Calendar here.
The second video, Leap Year and Leap Day, is much shorter and lends itself to a listening comprehension task for Básico (elementary) students.
Self-study activity:
Watch the video and complete the blanks in the transcript with the missing figures.
Today is the rarest day in our calendar: February (1) ... is a day that occurs only once every four years. That means this year has an extra day, making it a leap year.
A Leap Year is when the calendar year is extended to have (2) ... days - adding February 29th to the year. Leap years are added to the calendar to keep it working properly. The 3 (...) days of the annual calendar are meant to match up with the solar year. A solar year is the time it takes the Earth to complete its orbit around the Sun-about one year. But the actual time it takes for the Earth to travel around the Sun is in fact a little longer than (4) ... days. It is about (5) ... days, (6) ... days, (7) ... hours, (8) ... minutes, and (9) ...seconds, to be precise. So the calendar and the solar year don't completely match-the calendar year is a touch shorter than the solar year.
It may not seem like much of a difference, but after a few years those extra quarter days in the solar year begin to add up. After four years, for example, the four extra quarter days would make the calendar fall behind the solar year by about a day. Over the course of a century, the difference between the solar year and the calendar year would become (10) ... days! Instead of summer beginning in June, for example, it wouldn't start until nearly a month later, in July. So every four years a leap day is added to the calendar to allow it to catch up to the solar year.
There are a couple of strange traditions pertaining to leap years. For example, supposedly dating back to (11) ... century Ireland, women may make marriage proposals only in leap years, and in some cases only on February (12) ... . In Greece, it is believed that getting married in a leap year is bad luck.
Anthony, New Mexico is the self-proclaimed leap-year capital of the world. Every four years since (13) ... , residents throw a birthday party for people born on February (14) ... .
A person born on February (15) ... may be called a "leapling." In non-leap years, these people often celebrate their birthdays on either the last day of February or the first day of March.
Key:
(1) 29th (2) 366 (3) 365 (4) 365 (5) 365¼ (6) 365 (7) 5 (8) 48 (9) 46 (10) 25 (11) 5th (12) 29th (13) 1988 (14) 29th (15) 29th
