BACKGROUND:
Weather is a phenomenon that children have
experienced. They learn early to look outside before they dress to play
outdoors. Television helps children "see" other types of weather
around the world. So even though they don’t experience it, they are familiar
with the word. Some children have never seen snow, lightning, or a tornado.
However, stories about severe storms have always entertained children.
Thunderstorms are generated by temperature
imbalances in the atmosphere. 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.
Lightning is an effect of electrification
within a thunderstorm. As the thunderstorm develops, interactions of charged
particles produce an intense electrical field within a cloud. A large positive
charge is usually concentrated in the frozen upper layers of the cloud, and a
large negative change, along with a smaller positive area, is found in the
lower portions. Thunder is the sound produced by the explosive expansion of
air heated by a lightning stroke. When lightning is close, the thunder sounds
like a sharp crack and more distant strokes produce growling and rumbling
noises. Because the speed of light is much greater than that of sound, we see
a lightning bolt before we hear the thunder.
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, drain. 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 mountain 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 straight 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:
- This introductory coloring exercise has
the students looking at rain, snow, and sun dominated weather. Before the
students color, direct their attention to some of the characteristics of that
specific type of weather.
- You might also want to go over some
other weather types. Below is a list that can help guide your discussion.
Rain: Comes from clouds; wet liquid; different types
of clouds produce different intensities of rain.
Snow: Comes from cold clouds; solid water; always has
a hexagonal shape (an ice crystal grows in this pattern).
Sun: Clear day; depending on where the sun is in the
sky controls how hot it is.
Hail: Frozen rain (not a crystal like snow).
Hurricane: High winds, lots of rain.
Tornado: High winds that swirl around violently.
