Download What is a System? - Spokane Public Schools

What are open and
closed systems?
I can describe a system based on inputs, outputs and
boundaries.
I can defend whether a system is open or closed.
Remember the definition of a
system…
Two or more parts, working together,
to perform a function.
 Matter and energy flow through
systems.

Adding to our definition…
Two or more parts, working together, to perform
a function.
 Matter and energy flow through systems.
 Input– An input is something that enters the
system. It can be matter or energy.
 Output– An output is something that leaves the
system. It can be matter or energy.



Subsystem – a subsystem is a system that is
part of another system. It’s a system within
a system.
Boundary – the outside border of a system
Input…
In order to carry out their purpose,
systems need an input of some kind.
• Matter
• Energy
Output…
Outputs from a system can
include:
• Matter
• Energy
Sometimes the output from one
system can become the input for
another system.
Open and closed systems…
Open Systems
• An open system is
a system in which
both matter and
energy can enter
and leave.
• What kinds of
energy are inputs
and outputs for this
system?
• What kinds of
matter are inputs
and outputs for this
system?
Closed Systems
• In a closed system,
matter cannot enter
and leave.
• Only energy can enter
and leave.
• What kinds of energy
are inputs and outputs
for this system?
• Why can’t matter enter
or leave the system?
Open or Closed? Why?
Open or Closed? Why?
Boundaries can change…
When the boundaries of a system
change, the system can become open
or closed
 Boundaries can physically change, for
example when part of a forest is cut
down or a container is sealed.
 We can change boundaries when we
want to study a smaller or larger aspect
of the system.

The soda
can is a
closed
system.
Change the boundaries…
The soda can
becomes an
open system.

Plants are open systems. They have parts
that help them survive and grow. They
input energy – light, and matter – water,
carbon dioxide, minerals. They output, or
give off, matter - oxygen, new leaves …
Change the boundaries…


If the boundary is
expanded to include
the whole terrarium
that the plant is a part
of, then we are
studying a closed
system.
Light and heat energy
can flow, into and out
of, the system. No
matter can leave or
enter the terrarium.
Pick a system…
Think of a system.
 Decide if it’s open or closed and write
down your reasons.
 Change the boundaries you used to define
your system.
 Decide if it’s open or closed and write
down your reasons.

Based on “Teaching Systems as a
Framework for Understanding”.
Martha Mather and Vicky Smoot,
NSTA Area Conference, Dec. 2011.