Stella Report

Title  :Pendulum story

Introduction :

Teaching and learning simulation

Simulation is the imitation of the operation of a real-world process or system over time. The act of simulating something first requires that a model be developed; this model represents the key characteristics or behaviors of the selected physical or abstract system or process. The model represents the system itself, whereas the simulation represents the operation of the system over time. A computer simulation is an attempt to model a real-life or hypothetical situation on a computer so that it can be studied to see how the system works. By changing variables in the simulation, predictions may be made about the behavior of the system. It is a tool to virtually investigate the behavior   of the system under study. Computer simulation has become a useful part of modeling many natural systems in physics, chemistry and biology, and human systems in economics and social science which is also known as the computational sociology as well as in engineering to gain insight into the operation of those systems. A good example of the usefulness of using computers to simulate can be found in the field of network traffic simulation. In such simulations, the model behavior will change each simulation according to the set of initial parameters assumed for the environment. The work builds on the established literature which highlights the importance of activities which make implicit reasoning explicit teacher guidance which builds upon pupils’ ideas and teachers interpreting shared experience to bridge the gap between scientific conventions and informal ideas. Thompson, Simonson and  Hargrave (1996) defined simulation as a representation or model of an event, object or some phenomenon. In science education a computer simulation according to Akpan and Andre (1999) is the use of the computer to stimulate dynamic systems of objects in a real or imagined world. Alassi and Trollip (1991) describe simulations in educational context that is  simulation is a powerful technique that teaches about some aspect of the world by limitating or replicating it. Students are not only motivated by simulations, but learn by interacting with them in a manner similar to the way they would react in real situations. In almost every instance, a simulation also simplifies reality by omitting or changing details. In this simplified world, the students solves problems, learn procedures, comes to understand the characteristics of phenomenon and how to control them or learn what actions to take in different situations.

Simulation can integrate into teaching and learning because simulations support learning by allowing a pupil to explore phenomena and handle experiments which would not be feasible in school.  Teachers can also focusing attention on underlying concepts and relationships. Simulations offer idealised representations that limit the range of operating variables to good effect. A teacher could focus on just one aspect of a concept, and be sure of always getting a good clean graph. Careful customization of resources might be needed to channel attention in a particular direction. Teachers used ICT to ease and speed cumbersome tasks. This enabled them to focus on the key ideas as well as making time available for discussing results. Data loggers displayed temperature readings so rapidly that pupils could analyse a pattern in a cooling curve graph. Normally they might only draw the graph. Teachers reported how hands-on such as simulation activities gave them time to interact with pupils. They could observe what was going on as they circulated, engaging learners in discussion and addressing their questions. Gathering information on pupils’ understanding is an important feature of teaching. The computer display enabled them to gauge progress readily. With a simulation, diagram or animation to hand, content was covered more quickly. Again, not having to draw repeatedly on the board, or handle physical apparatus, released time to concentrate upon learning, its consolidation and assessment. Students can build knowledge by integrating technologies . Teachers felt that technology could be used beside conventional practical experiments to enable students  to see what’s happening in the real world and what’s happening on the microscopic scale as well. Teachers would employ a visual aid or a practical demonstration in conjunction with a simulation. In some lessons teachers used technology to relate lesson content to prior learning and to reinforce that prior learning. This enabled students to engage with new activities. For example, pupils were expected to draw on graphical skills that had been developed in previous years. This skills training also helped to guard against misinterpretation of data logged graphs display and allowed pupils to make faster conceptual progress. In science process skills, simulations can activate process skill of students, which are the basic skills for scientific inquiry. These skills are classified in two main groups which are basic science process skills and integrated science process skills. Simulation can be used in distance learning education. The computer simulation make science accessible, make thinking visible, help students learn from each other and help students develop autonomous learning. In this case, students must have enough control lab equipment to start and stop an experiment and make appropriate adjustments. The experiment should be no more difficult to conduct than with the equipment physically present.

In simulation, the students will get motivation to carry out the experiment, for example we used stella, it can save our time and easy to do. We only need to run the experiment by adjusting the knob to vary the parameters to see any changes or differences between each parameters in the graph. So, when the students start interested to learn, their motivation to learn in order to get deep knowledge increase. Then, they can make prediction what will happen after carrying out the experiment by using simulation.

 The latest simulation in school nowadays is simSchool. This in an alternative idea for the preparation of teachers and the improvement of teaching which is simSchool is a “flight simulator” for teachers in the form of a simulated classroom game. The simSchool project addresses key systematic challenges of teacher education including fundamental conceptions of teaching and learning, organization of knowledge, assessment practices and results and engagement of a global community of practice in teacher education. Simulations provide multiple chances to practice and to learn and master new skills more rapidly and with less effort tha through experiences not mediated by computers. In teacher preparation, simulations that provide targeted feedback can develop teachers’ understanding and practice, and may be as effective as in classroom field experience. Students who practice with a simulator develop a deeper understanding because of their reliance on and experience of immersive multimedia.

Stella is System Thinking for Education and Research that offers a practical way to dynamically visualize and communicate how complex systems and ideas really work. Stella models provide endless opportunities to explore by asking “what if “ and watching what happens, inspiring the exciting moments of learning. Stella supports diverse learning styles with a wide range of storytelling features. Diagrams, charts and animation help visual learners or students discover relationships between variables in an equation. Stella is used to simulate s system over time, jump the gap between theory and the real world , enable students to creatively change systems , teach students to look for relationships and clearly communicate system inputs and outputs and demonstrate outcomes. The features os Stella are mappinmg and modeling, simulation and analysis and communication.

         

Simulation at school in Malaysia   provide students to learn the subject in deep learning. This is because they can understand about the topic that they learn because they can observe thoroughly the experiment. Simulations can be used as effective means for teaching or demonstrating concepts to students. The used of graphics and animation  help to build an interactive learning for students. For examples the uses of computer simulations in science education gives students the opportunity to observe a real world and interact with it. In science classrooms, simulation can play an important role in creating virtual experiments and inquiry. Problem based simulations allow students to monitor experiments, test new models and improve their intuitive understanding of complex phenomena. Simulations are also potentially useful for simulating labs that are impractical, expensive , impossible or too dangerous to run. Simulations can contribute to conceptual change and provide open-ended experiences for students. It also provide tools for scientific inquiry and problem solving experiences.

         

Objectives :

1) to understand the simulation that can integrate into teaching and learning.  

2) to understand the stella which is important for teachers and students.

3) to understand the concepts of pendulum.

Results:

                            

Figure 1 :normal 

            

Figure 2 :mass of the ball

         

                                                     Figure 3 :initial displacement

                                                        Figure 4 :length of string

Discussion :

Simple pendulum is an excellent approximation of an isolated system. During its downswing, Earth’s gravity does work on the pendulum to transfer gravitational potential energy into kinetic energy .On the  upswing, gravity transfers kinetic energy back into gravitational potential mechanical energy of constant. The pendulum is a body suspended from a fixed point so as to swing freely to and fro under the action of gravity. Its regular motion has served as the basis for measurement, as recognized by Galileo.Huygens applied the principle to clock mechanisms. Other applications include seismic instrumentation and the use by NASA to measure the physical properties of space flight payloads. The underlying equation is at the heart of many problems in structural dynamics. Structural dynamics deals with the prediction of a structure’s vibratory motions. Examples include the smoothness or bounciness of the car you ride in, the motion that you can see if you look out of the window of an airplane in a bumpy flight, the breaking up of roads and buildings in an earthquake, and anything else that crashes, bounces or vibrates. With this pendulum motion as point of departure, complex structures can be analyzed. The pendulum serves as an illustration of Newton’s Second Law, which states that for every force there is an equal and opposite reaction. The simpler experiments illustrate another of Newton’s laws,namely, that a body in motion continues in motion unless acted upon by another force. The pendulum offers an extensive array of experiments that can be done using easy to obtain, inexpensive materials.The measurements require no special skills and equipment. The graphical results of each experiment  given, and can be compared to the results calculated from a simple equation if desired.

A pendulum is a weight suspended from a pivot so that it can swing freely.  When a pendulum is displaced sideways from its resting equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released, the restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. A pendulum swings with a specific period which depends mainly on its length.  When given an initial push, it will swing back and forth at a constant amplitude. Real pendulums are subject to friction and air drag, so the amplitude of their swings declines. The period of swing of a simple gravity pendulum depends on its length, the local strength of gravity, and to a small extent on the maximum angle that the pendulum swings away from vertical, θ₀, called the amplitude. It is independent of the mass of the bob. If the amplitude is limited to small swings,  the period T of a simple pendulum, the time taken for a complete cycle. For small swings the period of swing is approximately the same for different size swings: that is, the period is independent of amplitude. This property, called isochronism, is the reason pendulums are so useful for timekeeping.  Successive swings of the pendulum, even if changing in amplitude, take the same amount of time. For larger amplitudes, the period increases gradually with amplitude. The three different types of oscillation that are free, damped and fixed oscillation. Free oscillations occur while the pendulum is sets to its displacement and is moving in its to and fro motion it does not experience any force that prevents it from continuing this motion. Such forces that prevent free oscillation is,  air resistance. Damped oscillations occur while the pendulum is set to its displacement and is moving in its to  and  fro motion, experiences a force, or a medium that affects its motion. A forced oscillation occurs while an object is used to force or more pendulums into motion. An example of this is by using a driving pendulum to control the displacement of a set of 4 pendulums, which move as a result of the driving pendulum being displaced. Another example is using a vibrating tuning fork to force a stretched string to vibrate and set the pendulum into motion.

The aim of this experiment was to determine the   factors that  will affect the rate of oscillation of a pendulum, where oscillation is from the amplitude to the equilibrium to the amplitude. In order to find out the aim it is needed to find out the length, mass, or the amplitude, which are  factors, that may affect the rate of oscillation. The mass can be tested by changing the mass added onto the string while keeping the length of the string the same, and the amplitude of the string the same, which is   the amplitude is the distance from the equilibrium. In order to test the length, the mass and the amplitude are kept the same. And when testing the amplitude, the mass and the length are kept the same. For each of the factors tested the rate is needed to be calculated by figuring out the frequency and period. When the frequency is the number of complete oscillation in each second, and the period is the amount of time needed for one complete oscillation. The frequency is calculated by number of oscillation divided by the number of second in this case is 10 second. While the period is calculated by the number of second (10sec) divided by the number of oscillation. Once the pendulum starts to move, there are name for the aspects of its movement. The size of a swing is called the amplitude. The amplitude is measured in degrees, in which the same degrees that used to measure angles in geometry. One complete swing back and forth is called cycle . the time it takes for a pendulum to complete one cycle is called the period and the number of second is called frequency.

For the first graph is the normal one. During running the experiment, we do not change the parameter that is we only fix the mass of the ball which is the mass of the ball is 1.0 g , with initial displacement of  0.1 m and the length of the string is 1.0 m. The graph shown that the displacement or highest amplitude of the graph is 1.0 m with the gravity only. Then the parameter is changed with using the mass. The purpose that we manipulate the mass of the ball is we want to see the graph form and to know that whether the mass of the ball affect the period and frequency and amplitude of the pendulum motion.  So after running the experiment, it found that the period, frequency and amplitude is same when the different mass are used. The mass that are used are 0.50 g, 1.50 g, 1.82 g and 2.0 g. the driving force for pendulum is gravity. If the pendulum has twice the mass, gravity pulls twice as hard. Mass is also how hard the ball resists the force it feels. A pendulum with twice the mass feels twice the pull, but also has twice the resistance to that pull. These two effects balance out. A pendulum with twice mass still experiences the same effect. The mass of  ball does not affect how it moves. This is proven by the fact that in the equation v=2gh, the mass on both sides of the equation cancel each other out. For the second parameter we used initial displacement. The initial displacement 0.05 m, 0.12 m, 0.20 m and 0.12 m are use. When the initial displacement increase, the height of displacement also increases, the potential energy increases, so kinetic energy also increase but the time period remains same. For the third parameter, that is length of the string, with 0.5 m, 1.2 m , 1.6 m and 2.0 m. as the length of the string increases, so the period of the swing also increase. For the same linear amplitude, as the length increases, the displacement or height through which the ball  also decreases. Hence, when the height decreases, the kinetic energy will decrease, so also causing the potential energy to decrease. Velocity therefore decreases. When the velocity decreases, time or period will increases. When the length is increased to be longer, the frequency slows. When the length is increased N times, the frequency decreases by 1√N.


Last but not least, simulation play an important role in teaching and learning. This is because, the motivation of students to carry out experiment increases. Students only need to changed the parameter in stella in order to see the graph. They also can understand about the experiment very well instead of carrying out the experiment not using simulation. Students can relate the variables that can be made during the experiment. The teachers can also guide them in order to carry out the experiment. After doing the experiment, the students can expect what they learn about the experiment. So, they can relate the experiment and theories very well. 

Conclusion :

As a conclusion from the experiment, there are two factors that affect the period, frequency and amplitude of the pendulum. In this case, initial and length of the string affect the period , frequency and amplitude of the pendulum while the other parameter that is mass of the ball do not affect the motion of the pendulum. As the length of the string increases, the period of the swing also increases. , as the length increases, the displacement or height through which the ball   also decreases. Hence, when the height decreases, the kinetic energy will decrease, so  causing the potential energy to decrease, velocity  therefore decreases. When the velocity decreases, time or period will increases. When the length is increased to be longer, the frequency slows. When the length is increased N times, the frequency decreases by 1√N. For the initial displacement, when the initial displacement increase, the height of displacement also increases, the potential energy increases, so kinetic energy also increase but the time period remains same. For the mass, it does not affect the motion of the pendulum. A pendulum with twice the mass feels twice the pull, but also has twice the resistance to that pull. These two effects balance out. A pendulum with twice mass still experiences the same effect. The mass of  ball does not affect how it moves. This is proven by the fact that in the equation v=2gh, the mass on both sides of the equation cancel each other out.