This document provides information about a practical report on the STELLA simulation software. STELLA allows users to construct dynamic models that simulate biological systems using stocks, flows, converters and connectors. The report discusses three graphs generated using STELLA that model the relationship between rat and owl populations and palm oil production. The graphs demonstrate how increasing rat populations and decreasing owl populations can negatively impact palm oil yields over time. STELLA provides an engaging way for students to explore variables and conduct experiments to better understand complex systems.

1. Course name: Information And Communication Technology
In Science
Course code: SSI3013
Practical report on: Systems Thinking for Education and Research
(STELLA) Report
Lecturer: Encik Azmi Bin Ibrahim
Name Lecture Group Matric number
Aimi Fatihah Bt Muhammad Fauzi B D20151071003
Najwa Husna Bt Saahwal B D20151070957
Siti Khadijah Binti Khalid B D20151070972
Nurul Najiha Husna binti Baharudin B D20151070960

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INTRODUCTION
Referred to Oxford Dictionary, simulation has been defined as a model of a set of
problems or events that can be used to teach someone how to do something or the process of
making a model. Stella is one of the flexible computer simulations modelling package with an
easy, intuitive interface that allows users to construct dynamic models that realistically simulate
biological systems. STELLA is short for System Thinking, Experimental Learning Laboratory
with Animation. It has been introduced by Barry Richmond in 1985.
The program, distributed by isee systems which allow users to run models created a
graphical representation of systems using four fundamental building blocks. It has been used in
academia as a teaching tool and has been utilized in a variety of research and business
applications. It is because of its simplicity relative to more complex modelling languages;
STELLA has been cited as a useful tool in educational settings.
The inventor viewed most of education as assimilating content and proposed system
thinking as a remedy to this model. So, in 1987 High Performance Systems released a guide to
STELLA encouraging its use in academic settings. Many textbooks have been published that
teach modeling and system thinking using this software.
There are some functionality and features of STELLA. It was complete package of
modeling software that consist diagrams, charts, and uses animation help visual learners to
discover relationships between variables and helps simplify model building. It also handles time
series, sensitivity and simulation models well and has a drag and drop modeling interface. Users
may create graphical models of a system using four fundamentals such as stocks, flows,
converters and connectors. Relationships between converters (which convey transforming
variables) and other elements may be drawn with converters. Users also are able to input value
for stocks, flows and converters.
In other hand, STELLA runs one window at a time meaning that only one model can be
run at any given moment. The program’s native film formats are dnoted either by an .stm, .stmx,
.itm or .itmx. STELLA also uses the emerging XML-based standard for storing models, XMILE.
The languages run of Microsoft Windows and OS X and its most recent release was version

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10.1.2. in 2012, two researchers released StellaR, software which can translate STELLA models
into the R programming language.
DISCUSSION
Graph 1
This Stella software provides the exploration of the model and conducts the experiments
for all users. Stella is the best medium in education for instance, in order to enhance students’
motivation and their predictions on the results if they changed the variables by running the
experiment themselves. So, the purpose of this attempt is to develop a model of a system that
illustrates the effect of palm oil plant based on the population of owls and rats.
There are few buttons that can be click in order to see how the simulation is functioning.
The buttons are ‘run’, ‘stop’ and ‘pause’ and it also provides knob for students to manipulate the
variables. All the buttons and the knob can be click and manipulate by students to see what will
happen to the simulation graph. Exploring is an important element before students start to
conduct any experiment as they will be more eager about the experiment and the important thing
is they can relate the experiment with the theories they have learnt.

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For the beginning, students may set the knob that represents the number of rats and the
number owls. According to the picture above, the user have set the left knob to 20000 that
represents the population of rats and 12 on the right knob that represents the population of owls.
After the variables has been set, students can click the ‘run’ button to see what kind of graph will
the software produces. In addition, the software also provides the ‘slider’ for students to see how
many fruits are harvests and also how many fruits are damages caused by the increasing of the
rats in the plantations.
According to the graph provided in the picture, it shows that the population of rats keep
increases when there is a drop in population of owls. In the meanwhile, the production of palm
oil still increase by years even the population of rats has increases for a few years. Here, students
can noted that the increases of rats in the plantations give the big impact on the production of
palm oil. So that, the population of owls plays an important role in order to increase the
production of palm oil.
The picture above is to demonstrate to the student on how to use this simulation and see
the relationship among the variables on the graph. This simulation enables them to know how the
scientists do their work every day. Moreover, this simulation can make the students to be more
interested to conduct experiments after this, because they are able to manipulate the variables
and see how the results produce.

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Graph 2
The knobs used in this simulation purposely to see the effect of owls’ population and rat
populations towards the palm oil plants. This can be done by rotating the knobs to the left or
right in order to adjust the number of populations for both owls and rats. In this graph, the rat
population was set at 28000 while owls’ population is at 18. It can be compared with the first
graph where the number of rats is at 20000 while the number of owls is at 12. So that we can see
a very significant change between graph 1 and also graph 2.
From the graph, we can see that the population of owls increases slightly at the beginning
however after a few years, it started to decrease drastically to zero. The population of rats is very
low at first while the number of palm oil plants production is slowly increasing throughout the
year. However, after a few years the population of rats started to increase gradually because of
there were no owls that acts as a predator to those rats. Therefore, the palm oil production was
also started to decrease gradually.
After another several years, the population of rats started to increase rapidly so it
resulting in rapidly decreasing in number of palm oil plant because it cannot tolerate with the rat
populations anymore.

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Based on this graph, the simulation shows the relationship of owls and rats population to
the palm oil productions. We can see the significant change when there were increasing number
of rats and decreasing number of owls in the production of palm oil plants. We can also conclude
that there was equilibrium among these three variables. Thus, in order to cope with this situation,
some biological methods can be implement for instance the biological control method where we
can control the number of rats by increasing the number of owls in order to get a huge amount of
palm oil production.
Graph 3
Next, by using the stimulation student can generate data by prediction. The knob is used
to manipulate the variable by increase or decrease the population of owl and rat to see the effect
of the palm oil plant. Before that, the variables were manipulated which is both increasing the
population of rat and owl. For the third picture, only the value of the owl population has been
decrease.
After changing the value of the owl population, the graph of the owl will slightly down
and at the end will continuously constant. From the straight line graph also does not mean that no
interaction is occurred but it can conclude as the condition stable. From the graph student can
predict that the amount of owl increase the population of rat. Soon, the amount of rat will not
reduce because from the manipulating variable by decreasing the population of owl, we found
that there an excessive population of rat not being eaten.
When we look at the pattern of the graph, the population of the rat pattern are closely
related as it is inversely proportional to the population of oil palm plant’s pattern. The interaction
is simple. The owl population act as a predator, so the variable has been manipulated by the
student causes the outcomes of the oil palm plant population to be reduced. The oil palm plant is
the main source. If not all the rat eat by the owl so it need more food supply. Then, the oil palm
plant will reduce slowly.

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Furthermore, it shows that the population of rat will increase and also affected the source
of oil palm plant to decrease too. From the pattern of graph, the students are able to predict the
outcomes that happen for the next experiment if they know already what actually the pattern of
the population of rat, population of owl that depends by the main source of oil palm plant. If the
rate population of owl increase the rate population of rat decrease while if the rate of rat increase,
the rate of owl will increase too.
As this graph are not too complex to be interpreted by the students. It will trigger the
student engagement towards these activities to be active. They will participate to formulate a
new question and predict their own trend of outcomes for the next experiment. They can handle
all the knowledge and transfer the knowledge to a new problems and situation that were given by
the teachers.

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ADVANTAGES
STELLA gives many advantages in teaching and learning process. One of the advantages
is the teaching and learning process will become more interesting and exciting. It is because it
helps students or learner to explore everything in various types of experiments. They also can
enjoy the learning process and just not imagine on what have been taught by their teachers.
Next, simulation software helps students to be more focus and extra knowledge to
interpret data from the diagrams and graphs. Besides, in the same time it also helps to increase
the level of curiosity among students and improve confidence between them and to put more
effort on that experiment.
Other than that, it also can help the teachers to teach the abstract content to the students.
It is mean that, the simulation can make the student easy to understand as they can use the
simulation and not just imagine on what have been taught by the teacher. Other advantages of
using simulations are very quick development of complex models, short learning cycles and no
programming is needed. So there will be minimal errors occurred.
STELLA also helps to save the cost because teachers do not need to provide the
apparatus and materials for the experiment. Just use the simulation software students can run out
the experiment in a short time and students also will discover new things such as different
hypothesis from the variables. STELLA also can be used in geosciences or medical field to
investigate the effect of changes without producing a physical prototype. Besides, it also can be
used to investigate situation that would be dangerous in real life.
It also encourages students to inspire doing the experiment and helps passive
students to be more active and involved in the experiment or the activity very well.

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DISADVANTAGES
However, this simulation also gives disadvantages to the students that do not have
computer or limited availability of computers. They will not have the opportunity to explore after
they have learnt in class. Their learning process will happen only in the class. In addition, this
simulation also can give a big problem to the users that do not know how to use computer.
The users need to do two things in one time, which are learning about the computer and
also learning about the simulation. So, may be the user will be lag behind the others. Besides,
many simulations require intensive pre simulation lessons preparations. So, it takes time if
students want to use the simulation in a short period.
High cost of software also include as the disadvantages of the simulation. Only the trial
one can be used by the users. But, after 30 days, it cannot be use anymore. In addition, limited
scope of applicability and also limited flexibility. This is because the variation of the topics is not
too many. Some of them may not fix with the users specific.
Next, learn these simulations models also take time so it required additional training. As
we know, not everyone has been good in IT skills. So, before use this simulations, users need
spending more time to explore how to use this software before to use it.
CONCLUSION
Simulation is a suitable medium to be used in the school because it can motivate students
in learning. Simulation motivate students by keeping them actively engaged in the deep learning
process in order to solve the problems and make decisions to make the simulation run. As the
simulation runs, it is modelling a dynamic system in which the learner is involved. Thus,
participation in simulations enables students to engage in systems by thinking and enhances their
understanding of the systems as well as the science concepts. Furthermore, students will become
more exciting and inspiring in study because most of them like to do something rather than just
hearing to something. However, finding a good simulation in teaching is quite challenging for
teachers, but if the teachers know what their students need, it can be easier for the teachers.