Diverse learners, including students with a variety of disabilities, are often academically delayed. This delay can exacerbate the behavioral problems that diverse learners have when they become aware that their peers are academically further along than they are. Diverse learners also often have difficulties grasping core concepts and distinguishing insignificant details from important points. Often, diverse learners have a greater difficulty learning than the average student and so they fall behind, only to be faced with learning more material in less time.
To teach more in less time to students with greater learning difficulties requires that instruction be organized around "big ideas." Big ideas are concepts and principles that facilitate the most efficient and broadest acquisition of knowledge across a range of examples. By organizing and prioritizing information around fundamental concepts, big ideas maximize student learning because "small" ideas can often be best understood in relationship to larger, "umbrella concepts." Organizing information around big ideas means that (a) less information is learned, but the information has more power, and (b) treatment of information is commensurate with its level of importance (Dixon, Carnine, and Kameenui, 1996).
Big ideas in science do four things. First, they represent central scientific ideas and organizing principles. Second, they have rich explanatory and predictive power. Third, they motivate the formulation of significant questions, and fourth, they are applicable to many situations and contexts common to everyday experiences.
Convection is a big idea taught in the Earth Science videodisk program. The big idea of convection ties together geology, meteorology, and oceanography. An in-depth understanding of convection allows one to predict changes in the earth. Around the convection cell are various contexts where changes in the earth can be predicted based on an understanding of the principles of convection. Convection explains many of the dynamic phenomena occurring in the solid earth (geology), the atmosphere (meteorology), and the ocean (oceanography). Plate tectonics, earthquakes, volcanoes, and the formation of mountains are all influenced by convection in the mantle.
Similarly, the ocean currents, thermo-haline circulation, and coastal upwelling are influenced by global and local convection. In turn, the interaction of these phenomena in the earth and the atmosphere results in the rock cycle, weathering, and changes in landforms. The interaction of these phenomena in the ocean and in the atmosphere influence the water cycle, wind- driven ocean circulation, El Nino, and climate in general. Learning a big idea well translates into a deep understanding of much content.
from:
http://www.rit.edu/~easi/itd/itdv5n12/article3.htm