| NSES Content Standard Unifying Concepts
and Processes:
Systems, order, and organization Grades K-12, page 116 The goal of this standard is to think and analyze in terms of systems.
Thinking and analyzing in terms of systems will help students keep track
of mass, energy, objects, organisms, and events referred to in the other
content standards. The idea of simple systems encompasses subsystems as
well as identifying the structure and function of systems, feedback and
equilibrium, and the distinction between open and closed systems.
|
Benchmark 11A Common Themes: Systems
Grades 6-8, page 265
A system can include processes as well as things.
Benchmark 11A Common Themes: Systems
Grades 6-8, page 265
Thinking about things as systems means looking for how every part relates
to others. The output from one part of a system (which can include material,
energy, or information) can become the input to other parts. Such feedback
can serve to control what goes on in the system as a whole.
Benchmark 11A Common Themes: Systems
Grades 6-8, page 265
Any system is usually connected to other systems, both internally and
externally. Thus a system may be thought of as containing subsystems and
as being a subsystem of a larger system.
Benchmark 11A Common Themes: Systems
Grades 9-12, page 266
Understanding how things work and designing solutions to problems of
almost any kind can be facilitated by systems analysis. In defining a system,
it is important to specify its boundaries and subsystems, indicate its
relation to other systems, and identify what its input and its output are
expected to be.
Benchmark 11A Common Themes: Systems
Grades 9-12, page 266
The successful operation of a designed system usually involves feedback.
The feedback of output from some parts of a system to input for other parts
can be used to encourage what is going on in a system, discourage it, or
reduce its discrepancy from some desired value. The stability of a system
can be greater when it includes appropriate feedback mechanisms.
Benchmark 11A Common Themes: Systems
Grades 9-12, page 266
Even in some very simple systems, it may not always be possible to
predict accurately the result of changing some part or connection.
Benchmark 11C Common Themes: Constancy
and Change
Grades 6-8, page 274
Physical and biological systems tend to change until they become stable
and then remain that way unless their surroundings change.
Benchmark 11C Common Themes: Constancy
and Change
Grades 6-8, page 274
A system may stay the same because nothing is happening or because
things are happening but exactly counterbalance one another.
Benchmark 11C Common Themes: Constancy
and Change
Grades 6-8, page 274
Many systems contain feedback mechanisms that serve to keep changes
within specified limits.
Benchmark 11C Common Themes: Constancy
and Change
Grades 9-12, page 275
A system in equilibrium may return to the same state of equilibrium
if the disturbances it experiences are small. But large disturbances may
cause it to escape that equilibrium and eventually settle into some other
state of equilibrium.
Benchmark 11C Common Themes: Constancy
and Change
Grades 9-12, page 275
Things can change in detail but remain the same in general (the players
change, but the team remains; cells are replaced, but the organism remains).
Sometimes counterbalancing changes are necessary for a thing to retain
its essential constancy in the presence of changing conditions.
See also Chapter 11 Common Themes, Section A: Systems and Section C: Constancy and Change, for precursor ideas.