Over a span of
time, there is a dramatic change in the geomorphology of the earths surface. When
viewed from above, it is very clear that the Earths surface has changed dynamically
because of natural forces and because of mans intervention into natural geologic
Image comparison over a significant span of time will allow teacher and
student to view the environmental impact that man has had on an area. The deforestation of
the Amazon rainforest and the on-going change in the course of the sediment-laden streams
are clearly defined through image comparison. Deforestation involves the cutting down,
burning and damaging of forests. Most of the clearing is for agricultural purposes and
commercial logging. The worlds population has increased causing a real need for
survival. However, at what cost? Students will be able to compare the change in the
landscape through time and research the reasons why the deforestation occurred and its
profound effects on global climate and the possible loss of unidentified species. A
brainstorming for solutions to this and other problems will allow students to problem
solve and realize that their environment is influenced by the decisions made by others.
Students will have the capability to do an in-depth image comparison over time and enter
activities like the NASA Student Involvement Program.
|Students might choose to hypothesize as to
what effect the burning and clearing technique has on the topsoil. Rainwater carries away
the topsoil, which goes into the river system. The turbidity or clarity of river water is
an indicator of the amount of sediment that is being transported. If too much sediment is
transported and the velocity of the river decreases the sediment is deposited in lobes.
These will cause the river to change its course and become braided. This is evident
in satellite imagery. The change in the color of the vegetation and the addition of
sediment to the rivers will be evident in images taken by Skylab and by the GeoCam II
cameras. A decline in vegetation and an increase in sediment load of rivers clearly points
to a future environmental or agricultural problem.
|Rivers, deltas, and other natural fluvial and
coastal systems change through time. The formation of oxbow lakes, a changing flood plain,
the development or erosion of a beach or offshore island could be investigated with a
sequence of images that span several years. The tremendous diversity of fluvial systems
and its relationship to the accompanying geology of the area on a global scale could be
investigated by collaborative groups of students. Projects involving images taken by a
camera onboard the space shuttle have engaged the students into comparisons and
annotations of images from different geographic areas.
||Students might choose to study the development
of urban area and the transportation patterns (highways, roads and airports). This will be
another feature that will be evident when images of the same area are reviewed over a span
of time. The positive or negative impact of urban planning will clearly show up in images.
The students understanding and willingness to investigate a problem of their choice
has lead in the past to the development of excellent student projects. For example,
students have compared London to Charleston. These projects serve as models as they
represent excellence. Students do not limit themselves when given the freedom to expound.
Presentations in my classroom, though scientific in nature, are sometimes presented in
different methods such as prose. Students are given the opportunity to explore and present
in a manner of their choice.