Making a Better Calendar

Old calendar challenge

Our current calendar divides the 365-day year into 12 months, or 52 weeks plus one extra day. Find a better calendar system. For example, are 7-day weeks best? Is there any way to avoid needing a new calendar every year?


You can use the same calendar every year (except leap years, which have two extra days) if you make the extra day a special holiday, perhaps at the beginning or end of the year, not part of any week. C. Gahr suggests calling it January 0.

Gahr and H. Sheldon keep twelve 30- or 31-day months, as in the current and the popular proposed "World Calendar," sent in by R. Gatto and R. Cohen. A. Dunne and D. Trent propose thirteen 28-day months, so that every month has exactly four weeks and always starts on the first day of the week, as in the more radical proposed "13 Month Calendar."

R. Cohen sent in the even more radical "Secular Calendar," with 6-day weeks. J. Henry proposes 10-day weeks, with a third day off in the middle of the week. M. Wright proposes 5-day weeks with three 9.5-hour work-days. D. Barbalace proposes 5-day weeks with a 1-day weekend called "Restday," followed 4 shorter work-days - Tuesday, Wednesday, Thursday, and Friday "since nobody likes Monday." For more information see the Web for the calendar reform home page.

Global warming

Regarding the previous column on rising water levels: S. Miller, B. Oostdam, H. Sheldon, F. Thomas, R. Thomas, and D. Trent rightly remark that the melting ice "resting on the bottom" must include ice on land (and certainly not smaller chunks of ice sunken to the bottom - ice floats!) and suggest the additional contribution of the expansion of warmed ocean waters.

New challenge

J. Henry asks whether, on a sinking boat, it helps to make parakeets in the hold fly around. K. Reinecke asks whether an airplane gets lighter when the passengers eat a meal. What causes an airplane to get lighter during flight?

Send answers and new questions to:

Math Chat

Bronfman Science Center Williams College Williamstown, MA 01267

or by e-mail to:

The best submissions will receive a copy of the classic book "Flatland."

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