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Geomorphology and the Analysis of Change

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Over a span of time, there is a dramatic change in the geomorphology of the earth’s surface. When viewed from above, it is very clear that the Earth’s surface has changed dynamically because of natural forces and because of man’s intervention into natural geologic processes.

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 world’s 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.

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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.

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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.
A dramatic change in the geology of an area will prompt students to investigate the cause. The dramatic impact that a volcanic eruption has on the landscape will be best observed by a sequence of images taken over time. It will allow the teacher and students to view the total impact of the volcanic eruption on the landscape and to investigate how the environment recovers from such an event. To evaluate a change requires images of the same area over a span of time. The color images which will be taken by the GeoCam II cameras onboard the International Space Station, covering163km per side, will be ideal for this type of study. The first step will be to identify those factors that have changed after matching up the latitude and longitude of the area. The students will be able to speculate as to what forces (wind, volcanic, influence of water) caused the changes that they see. They will be able to identify the type of change, cite evidence as taken from the images and speculate as to the cause or causes of the change. This should lead them into an in-depth study as they investigate and even hypothesize as to what will happen to this particular geological area in the future if factors remain the same. Can Do teachers have involved their students in short-range research projects in the past. These were an effective learning tool. If students were able to evaluate and to actually see the geomorphic changes that areas undergo over time, they will engage in active learning and problem solving. This will provide them with a visualization of the changing face of the Earth through time.

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