Search
Classroom Capsules and Notes
send to a friend
Why December 21 Is the Longest Day of the Year
by Stan Wagon (Macalester College)
This article originally appeared in:Mathematics Magazine
December, 1990
Subject classification(s): Mathematical Physics | Applied Mathematics | Differentiation | Single Variable Calculus | Calculus | Trigonometry | Spheres | Solid Geometry | Plane Geometry | Geometry and Topology
Applicable Course(s): 4.18 Applied Math (Math Modeling) | 4.9 Geometry | 3.1 Mainstream Calculus I
This article is part of the Mathematics of Planet Earth 2013 Collection. An equally accurate title would be why the day of latest sunrise and the day of earliest sunset do not occur together and neither occurs on the shortest day of the year. Using simple geometry, trigonometry, and elementary calculus, the author describes the graphs of solar noon (at 44 degrees north latitude, i.e., at St. Paul, MN) and the graph of its derivative, the solar day and uses them to explain the sunrise and sunset times.
A pdf copy of the article can be viewed by clicking below. Since the copy is a faithful reproduction of the actual journal pages, the article may not begin at the top of the first page.
To open this file please click here.
These pdf files are furnished by JSTOR.
Capsule Course Topic(s):
To rate this capsule on a 1-5 scheme, click on the appropriate icosahedron:
 | |  |  | | Current rating: 2.9 | number of votes: 63 | |
| 1 | 2 | 3 | 4 | 5 |