Ask A Scientist© Environmental Earth Science Archive

      name         Johnny
 >    status       educator
 >    age          20s

 >    Question -   I'm trying to come up with a first grade explanation for
 > why it is cold in November though the sun is bright.  I know how to
 > explain the earth's tilt and rotation to older students, but I was
 > wondering if you have a good six-year-old explanation for this.  Thank you!


There are several reasons the average temperature in November is cooler than
that of July, but the main one is that the sunshine is less "intense" in
November. The explanation of "why" it is less intense is due to the tilt of
the earth on its axis relative to the orbit of the earth around the sun, and
you are right in that the explanation is probably beyond understanding of 6
year olds.

But, you can perform an experiment that will demonstrate the principle, and
will help first-graders understand the reason. This works best in a darkened
room, but you can do it in a lighted classroom as well. Take an ordinary
flashlight, turn it on, and lay it horizontally on a shelf or table. This
light will represent the sun. Take a piece of cardboard, or even a sheet of
paper, and hold it perpendicular to the light beam, about 2 feet in front of
the flashlight. The beam should make a circle of light on the cardboard.
Now, keeping the cardboard about the same distance from the flashlight, tilt
the top of the cardboard away from the flashlight. The circle of light will
change shape from a circle to elliptical (oval), and will become larger and
less bright the more you tilt the cardboard.

Explain, that because the earth appears "tilted" in November, the sunlight
is spread over a bigger area, just like the flashlight beam, and this means
less light(and heat) to those areas. The farther north you go, the more the
apparent "tilt" and the colder the average temperatures. (There are other
factors that affect the average temperature, but are not really relevant to
this discussion).

I hope this explanation will help you in talking to your class about the
differences between summer and winter. And sorry for the delay in
responding...but this e-mail got filed in the wrong place..!

Wendell Bechtold, meteorologist
Forecaster, National Weather Service
Weather Forecast Office, St. Louis, MO
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