Teaching Science through a Systems Approach
Llewellyn, Douglas, Johnson, Scott, Science Scope
Mr. McKenna teaches seventh-grade science at Woodrow Wilson Middle School. The district's science curriculum for grade seven specifies the study of the systems in the human body. In Mr. McKenna's classes, students study the systems of the body independently and sequentially. The study of the human body begins with the digestive system, followed by the skeletal system, circulatory system, nervous system, and excretory system. At the conclusion of each unit, students are given a multiplechoice test to assess their ability to recall body parts and their functions.
Across the hall, Ms. Watkins also teaches seventh-grade science. Following the same curriculum, Ms. Watkins takes an atypical, metaphorical approach in her teaching. She commences the human body unit with a discussion about the commonalities that exist amongst an organization. Using the school as an example, she introduces the notion of a system to demonstrate how parts of a system are interrelated and how all the subsystems and parts of the subsystems act in concert to perform a specific function. Ms. Watkins familiarizes students with the concept of systems by discussing examples of engineering systems, natural systems, and social systems. To show an example of several familiar natural systems, she shows students typical food webs for several types of communities, including a forest, a pond, and a desert. She also compares that natural system to another system: a transportation map of the local bus system and commuter rail.
Students in Ms. Watkins class quickly understand how they are part of a system--be it a family, sports team, school, or community. Students come to grasp the idea that all systems, whether they are biological (like their body) or physical (like an electrical circuit), have inputs and outputs and that if one part fails the entire system is affected or may shut down. Once students gain an appreciation of a systems approach, Ms. Watkins prepares an introduction to the systems of the human body and an explanation concerning the connectedness and dependence that characterizes each of the body systems.
What is a system?
A system is a set of individual objects that interact and influence each other to perform a task or function. Like the pond and the transportation examples, a system can be living or nonliving, as small as a cell organelle or as large as the arrangement of planets in a solar system. The objects of a system can be almost infinite, including objects, organisms, machines or processes, ideas, numbers, or organizations (real or imaginary). Regardless of the system being studied, thinking in terms of systems involves thinking about relationships, connectiveness, and context--not content. As we shift our thinking from individual parts to the whole--from snapshots to the big picture--we change our thought processes into a systems-thinking approach. Whereas a non-systems-thinking approach focuses on sorting out the whole into its separate, discrete parts, a systematic thinking approach focuses on how components of a system perform together. A systems-thinking approach involves refocusing our understandings from objects to relationships, from contents to patterns, from structures to processes, from individuals to communities, and from microcosms to macrocosms. It's, as some say, "seeing the forest for the trees."
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Systems in life, Earth/space, and physical sciences
The food chain is a familiar middle level example of how one component of a system influences another. Take, for example, whales that feed on plankton and other microorganisms in the oceans. These aquatic mammals are part of a much larger system in our oceans. What role does the whale play in this system? What happens to the whale when it's unable to find enough plankton to survive? How does one population affect others in the ocean community? What would happen if whales became extinct? …