The water, or hydrologic, cycle is often at first perceived as a fairly simple, well understood cycle. Evapotranspiration (evaporation of water from plant leaves, stems and flowers) places water in the atmosphere. The water condenses and as precipitation returns to the earth as dew, frost, rain, snow or ice. Liquid water will eventually soak into the ground, becoming ground water, or runoff into streams and rivers, until it finally makes its way to the oceans. Closer examination, particularly by remote sensing, reveals a troubled cycle indicating numerous signs of stressed ecosystems on the planet. In this investigation, students will interpret and analyze remote sensing, and enrich their knowledge of the hydrologic cycle.
Outcome:
Appreciate remote sensing as a tool which has revealed problems involving the hydrological cycle
Analyze remote sensing imagery
Develop a working knowledge of graphics software
Suggested Grade Level & Duration:
Grades 5-8; 2 to 3 fifty-minute periods.
Materials:
Graphic Converter or ImageJ for Macintosh, or LView or ImageJ for Windows, to enable magnification of selected image areas, Landsat images of Garden City, Kansas, in 1972 and 1988 and Rondonia, Brazil in 1975, 1986, and 1992. Note that Graphic Converter is Shareware and ImageJ is in the public domain.
