About
this Daily Classroom Special:
Science to Go provides easy yet meaningful
science activities for grades k-8. Science to Go was written
by Barbara Smith, Magnet Coordinator at Harvard Elementary, Houston
(TX) and former Teachers Network web mentor.
The Equinox
What Is It?
The equinoxes are the two days each year on which the sun is directly
above the Earth's equator. They mark the beginning of fall, and
the beginning of spring. The upcoming equinox will be the Vernal
Equinox for the northern hemisphere, and the Autumnal Equinox
for the southern hemisphere.
What Difference Does It Make?
Well, as the Earth passes the equinox, all points on the Earth
will have 12 hours of sunlight and 12 hours of night. As it APPROACHES
equinox, the northern hemisphere's daylight hours are longer than
12 hours, but are decreasing. The southern hemisphere has more night
than daytime hours, and their daytime is lengthening.
This change TO more daylight at a more direct angle causes the
Northern Hemisphere to experience a warming trend that is the change
to Spring. The change to LESS daylight, at a steeper angle, causes
the Southern Hemisphere to experience a cooling trend that is Fall,
then Winter.
How Do You Participate?
- Explain the phenomenon to your students. You may want to access
the websites I have listed below.
- Determine how you will gather sunrise and sunset times. If
it is from meteorological bureau data, indicate your source.
(** Please strongly caution your students against looking directly
at sun, to avoid irreparable eye damage!)
Web Sites to Check Out
Universal
times for the vernal equinox
Equinoxes,
Solstices, Perihelion, and Aphelion for 1992-2005, U.S. Naval
Observatory | 
