C. Systems Thinking

A system is any collection of interacting parts that make up a whole. In a sense, all technologies can be thought of as systems. Furthermore, the ways in which objects are produced and used can also be thought of as systems, as technological objects all have a life cycle, being made from raw materials, used, and eventually being discarded, at which point they may be recycled or added to landfills. More broadly, there are many examples of systems that are not technological in origin or else are only partly technology: ecosystems, financial systems, political systems, and so on.

Beyond understanding that systems exist, citizens who are literate in technology and engineering should be comfortable with the broader skill of systems thinking, a set of cognitive tools that increases in sophistication and power over time. Systems thinking is the capability to investigate—or think about—a system using certain principles. It enables people to understand complicated situations that involve many interactions. For example, consider these principles: systems include sub-systems; any given system is typically part of one or more larger systems; and systems interact with other systems. These principles are important in thinking about the nation's transportation system, among other things. The transportation system consists of a vast network of roads and rails and millions of vehicles. It is dependent on a second system that extracts oil from wells halfway around the world and carries that oil in thousands of supertankers to huge refineries and from there to distribution points and gas stations. Since the combustion of fuels produces carbon dioxide, these systems affect the global climate system as well. Citizens who understand the effects of different fuels on the environment will be able to make decisions about what kind of automobile to purchase based on both these interconnected technological systems and the price of gas.

Systems thinking can be applied equally well to understanding systems other than purely technological ones—to analyze the way that communication technologies influence society and in turn are influenced by society, for example, or to think about the interplay between energy technologies and global climate change, and to predict future conditions given current trends and changes people may choose to make. It is a cognitive tool that helps people analyze problems they encounter in various settings and to propose solutions or determine reasonable courses of action. Simply put, systems thinking helps people understand how things are put together, how they function, and how they connect with other parts of the world, and it assists people in making informed decisions.

Key principles in the area of Systems Thinking that all students can be expected to understand at increasing levels of sophistication are as follows:

• Technological systems have parts that work together to accomplish a goal.
• Systems may include subsystems and may interact with other systems. Systems may also be embedded within larger systems.
• Dynamic technological systems require energy with more complicated systems tending to require more energy and to be more vulnerable to error and failure.
• Technological systems are designed for specific purposes. They incorporate various processes that transform inputs into outputs. Two important features of technological systems are feedback and control.
• Various methods can be used to increase the reliability of technological systems.

Fourth-graders should know that a system is a collection of interacting parts that make up a whole, that systems require energy, and that systems can be either living or non-living. They should also be able to look at a simple system, identify its various parts, and recognize the functions of these parts within the larger system.

Eighth-graders should be able to analyze a technological system in terms of goals, inputs, processes, outputs, feedback, and control. They should be aware that systems can interact with each other and be able to identify the subsystems and components of a device by using reverse engineering—the process of analyzing a system to see how it works in order to design a different device that performs the same function. Eighth-graders should also be able to trace the life cycle of a product from raw materials to eventual disposal.

Twelfth-graders should be aware that technological systems are the product of goal-directed designs and that the building blocks of any technology consist of systems that are embedded within larger technological, social, and environmental systems. They should also be aware that the stability of a system is influenced by all of its components, especially those in a feedback loop. (Negative feedback tends to stabilize systems while positive feedback leads to instability.) Students should be able to use various techniques to forecast what will happen if a component or process is changed.