My 11-year-old son asked me last night if there was an East Pole or West Pole.

I told him he should be able to figure that out for himself; I asked him the leading question “what is the definition of East?”.

It didn’t go well. Then he asked if it would be different on Mars if Mars was “upside down” compared to the Earth. That didn’t go well either – severe conflict of mental models.

They don’t teach geography (or in this case perhaps astronomy) very clearly in school.

But then dictionaries have huge trouble with this, too.

Here are my definitions:

East: The direction in which the Earth (or any planet) spins.

West: The direction opposite to East.

North: The direction 90 degrees to the left of East.

South: The direction 90 degrees to the right of East.

Compare that with any dictionary you like.

The general problem with numeric date formats is this – what does “04.07” mean? Is it July 4th or April 7th? Or April 2007? Maybe July 2004?

The answer is it’s ambiguous unless you have some other clues.  In general the separator is the clue; a dot (.) means it’s in Euro order (Day;Month;Year).  A slash (/) means it’s in USA order (Month;Day;Year) and a dash (-) means it’s in international (also Asian) order (Year;Month;Day).

So in general – don’t use MM.DD.YY date format ever.  That is confusing because DD.MM.YY (with dots) is one of the standard date formats in Europe, and MM/DD/YY (with slashes) is the most common format in the USA.  So using dots (European) with the USA order Month-Day-Year is doubly confusing.

If you must use USA order, use slashes (/) to help identify it.  If you’re going to use a Euro format, use the one that spells out the month (20 Jul 1969); at least it’s unambiguous.

Best of all is to use the ISO 8601 international format: YYYY-MM-DD.

For example, use 1776-07-04.

The dashes and the 4-digit year coming first indicate clearly that it’s in neither the Euro formats (04.07.76 or 4 July 1776) nor the USA formats (7/4/76 or July 4, 1776).

The ISO international format also has the advantage that it sorts correctly in a computer (dates will get sorted chronologically); neither the Euro nor USA formats do that.

The ISO format also happens to be the same format used in Japan & China, but that’s just a coincidence.

In general writing (when sorting order doesn’t matter) you can avoid the whole problem if you spell out the date instead of using numbers:

4 July 1776
July 4, 1776

These are both completely clear and unambiguous.