in the previous section
about systems functioning but purposely
left out some important aspect to the
process that is to say what the system
is processing and how well it does this
whether we are talking about a car
political system or a farm we are often
interested in answering the question how
well does it work that is to say what is
the ratio between the resources that the
system takes in and those that it
outputs
language of system theory this is called
the system's efficiency
answering this question may not be too
difficult if we are simply talking about
something like a steam engine but if we
wish to be able to reason about all
types of systems in this way the
question becomes a little bit more
difficult than it might sound so we need
to start by being clear about some of
the terms we are using
firstly a resource is essentially a
stored form of energy an ordered
structure that enables a system to
perform work examples of this might be
the food humans metabolize in order to
fuel our bodies or petroleum where
energy is stored in chemical bonds
the opposite of energy is entropy which
is the incapacity to perform work and a
measurement of the degree of disorder
within a system
whereas a stored form of energy is
called a resource a stored form of
entropy may be loosely equated to the
term waste an example of an entropy
system might be a vase that has fallen
on the ground and shattered the parts
are arranged in a random unordered
fashion making them incapable of serving
their intended function
energy and entropy are typically
measured using information theory that
is to say we can measure the degree of
order or disorder within a system in
terms of the information correlation
between its constituent elements the
more patterns there are between the
parts the less information it will take
to describe the system and thus the more
ordered it is said to be thermodynamics
is the area that studies energy in
relation to heat whilst energetics is
the area that studies energy on a
broader level within all physical
systems
the functioning of a system can be
either productive or consumptive a
function can be said to be productive if
the system takes in some resource from
its environment and performs work on
this resource by transferring energy to
it and thus outputting a resource of
greater value
an example of this might be simply
lifting an object off the ground when we
model this phenomena as a system we can
see that we inputted an object at the
low level of potential gravity and in
transferring energy from ourself to the
object by lifting it we output it an
object at a high state of potential
energy a resource that now has a greater
capacity to perform work than it did
before we performed this operation on it
inversely a function can be said to be
consumptive when the resource that was
inputted transfers its energy to the
system conserving this energy with the
systems boundary whilst outputting
entropy otherwise known as waste to its
environment
probably the simplest example of this is
the metabolic process of digestion
within mammals here the resource of food
is inputted to the system energy is
extracted from it and a waste product of
excretion is exported from the system
so we can define systems efficiency as a
ratio between energy inputted and the
energy output it but unfortunately what
is considered energy and what is
considered entropy is by no means
objective and is often relative to the
system's environment
to take an example of this a light bulb
consumes some amount of electricity as
its input and produces some amount of
light as its output though not all
electricity is converted to light some
is converted to heat energy with respect
to the functioning of the light bulb as
a light producer this heat would be
considered waste or entropy but if we
were interested in heating our house
then this excess heat energy may be
considered a resource in order to
understand this better we need to think
outside of systems that is start talking
about their environment and this is
where we will pick up in the next video