# The Math of Autumn Equinox

Today, is the first day of autumn (the autumnal equinox) – the time at which the Earth reaches a point in its orbit known as the equinox, where the sun shines directly on the equator, favoring neither the Northern nor Southern Hemisphere. For just one day, both hemispheres of the Earth experience 12 hours of daylight and 12 hours of darkness.

The great sandstone monoliths at Stonehenge in southern England are said to mark the autumn and spring equinoxes, as well as the summer and winter solstices, the longest and shortest days of the year respectively.

There is lots of math involved here to be shared with students from the geometry of Stonehenge to using trigonometry to calculate daylight hours for any latitude.

Try this math problem with your middle school students:

We all know that the further north we go the less sunlight we get in the winter.  Columbus, Ohio is at 40 north latitude. However, if you were living in Juneau, Alaska you would be at 60 north latitude. On the first day of autumn both receive 12 hours of daylight.  However, on Dec. 16th, the first day of winter, Columbus will receive 9.17 hours of daylight while students in Juneau will receive just 5.56 hours.

Compared to Juneau, how much more daylight will Columbus, Ohio receive on Dec. 16th?  Provide the answer in hours to two decimal places and as a percentage.

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