BACKGROUND:
The topography of an area can influence the
weather and climate. Topography is the relief of an area. If an area is close
to a body of water it tends to make milder climates. Mountainous areas tend to
have more extreme weather because it acts as a barrier to air movements and
moisture. One side of mountain can be dry while the other side is full of
vegetation.
Mountains can cause a physical barrier to
rain clouds. In this lab, students will construct a "mountain" and
rain clouds, to dramatize why one side of a mountain will have more water,
hence, more vegetation than the other side.
PROCEDURE:
- Give each group a metal pan or meat tray
and clay. Instruct students to create a mountain scene. You may want to use
small branches for trees. Aluminum foil can also be used to create an
appearance of a lake.
- Give each group a sponge. Make the
sponge wet. Students should pretend that it is a cloud full of water ready to
become rain or snow. Students love to watch the water run off the mountains.
Let each child be a rain cloud.
- Explain that a cloud is heavy when it is
wet, too heavy to get over the mountain. the winds are pushing it up, and as
it gets pushed up, it cools. It cannot get lighter and cannot go over the
mountain. By this time there is very little water left for the other side of
the mountain. If the mountain is high enough there will be a desert on the
other side. There are many examples around the country of this phenomenon
especial on the west coast where the mountains are high. The Coast Ranges acts
as a barrier to the Central Valley, and the Sierra Nevada prevents water from
getting into Nevada and Arizona, making them desert-like.
- If you have relief maps of the your
local area, you mind want to find any areas that might fit this model. Let the
students experiment with the sponge and mountain.
