BACKGROUND:
The troposphere creates conditions that
produce all weather including severe storms. Some areas are more prone to certain
conditions than others. For instance hurricanes commonly occur on the east
coast of the United States originating in the warm waters south or southeast
of Florida. Certain moisture and wind conditions in the troposphere
create different weather phenomena.
Thunderstorms, generated by temperature
imbalances in the atmosphere, are a violent example of convection. The warming
of the air near the Earth's surface and/or the cooling of the air above the
surface causes instabilities and convective overturning of various layers of
hot and cold air.
A severe thunderstorm may spawn a tornado,
a violently rotating column of air which descends from a thunderstorm cloud
system. On the average, tornadoes move about 30 miles an hour, however, some
move very slowly while others speed along at 60 miles an hour or more.
Floods are a natural and inevitable part of
life along the rivers of our country. Some floods occur seasonally when winter
or spring rains, coupled with melting snows, or torrential rains associated
with tropical storms. Drains, small tributaries, and river basins fill with
too much water, too quickly and overtop its bank. Other floods are sudden,
resulting from heavy localized rainfall. These flash floods are raging
torrents which rip through river beds, urban streets, coastal sections and
mountains canyons after heavy rains, and sweep everything before them.
Hurricanes are storms that start over
tropical waters. The blazing Sun beats down on the ocean waters day after day
and the air above this water gets hot. As cold air moves in, it pushes the hot
air up until the hot air reaches a cool layer of air. The water vapor
condenses very suddenly and becomes a driving rain. Cooler air from the
outside moves in, in a whirling motion, like water going down a drain. The
center or "eye" of the hurricane is calm, but all around it the
winds and rain are swirling.
PROCEDURE:
- There are many books and Internet sites
on different meteorological conditions where students can get more
information. In a book like Tornado Alert, the author weaves
information with a story. When having the students read this book, inform them
they are going to get asked questions. You may want to give the questions
before the class reads the book aloud, so students can take notes of the
answer. If you only have one book have certain students read a page in front
of the class.
- You may want to have the students play
with the "Tornado in a Bottle" before or just after you read the
book. Don’t quite tell them why they are playing. (You will later ask them
if this "model" of a tornado is scientifically accurate.)
- Ask the following questions to see if
students can transfer knowledge from a literature book. You can easily add to
the list.
