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Michael R. Gallis
The Easy Java Energizer model explores the relationship between kinetic, potential, and total energy. Students drag markers to create a 1-D curved track, then drag the motion marker to set an initial position on the track. The "hills" can be large or small in height. Click "Play" and watch the object travel along the user-created curve. Bar graphs of kinetic (KE), potential (PE), and total energy (TE), are displayed in real time alongside the curve. Below the energy chart, a graph of resulting force is also displayed. Download File Below
Editor's Note: This model is a simple, yet powerful way to introduce the Work/Energy Theorem. It can be easily adapted for middle school classrooms, and extended into an investigation of force vectors for high school physics courses.
The Energizer model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed.
Please note that this resource requires
at least version 1.5 of
Energizer Model source code
The source code zip archive contains an XML representation of the EJS Energizer Model. Unzip this archive in your Ejs workspace to compile and run this model… more... download 81kb .zip
Published: October 27, 2008
6-8: 4E/M1. Whenever energy appears in one place, it must have disappeared from another. Whenever energy is lost from somewhere, it must have gone somewhere else. Sometimes when energy appears to be lost, it actually has been transferred to a system that is so large that the effect of the transferred energy is imperceptible.
6-8: 4E/M2. Energy can be transferred from one system to another (or from a system to its environment) in different ways: 1) thermally, when a warmer object is in contact with a cooler one; 2) mechanically, when two objects push or pull on each other over a distance; 3) electrically, when an electrical source such as a battery or generator is connected in a complete circuit to an electrical device; or 4) by electromagnetic waves.
9-12: 4E/H1. Although the various forms of energy appear very different, each can be measured in a way that makes it possible to keep track of how much of one form is converted into another. Whenever the amount of energy in one place diminishes, the amount in other places or forms increases by the same amount.
9-12: 4E/H9. Many forms of energy can be considered to be either kinetic energy, which is the energy of motion, or potential energy, which depends on the separation between mutually attracting or repelling objects.
6-8: 4F/M3a. An unbalanced force acting on an object changes its speed or direction of motion, or both.
9-12: 4F/H1. The change in motion (direction or speed) of an object is proportional to the applied force and inversely proportional to the mass.
9. The Mathematical World
9B. Symbolic Relationships
6-8: 9B/M3. Graphs can show a variety of possible relationships between two variables. As one variable increases uniformly, the other may do one of the following: increase or decrease steadily, increase or decrease faster and faster, get closer and closer to some limiting value, reach some intermediate maximum or minimum, alternately increase and decrease, increase or decrease in steps, or do something different from any of these.
9-12: 9B/H4. Tables, graphs, and symbols are alternative ways of representing data and relationships that can be translated from one to another.
11. Common Themes
6-8: 11B/M2. Mathematical models can be displayed on a computer and then modified to see what happens.
9-12: 11B/H1a. A mathematical model uses rules and relationships to describe and predict objects and events in the real world.
9-12: 11B/H3. The usefulness of a model can be tested by comparing its predictions to actual observations in the real world. But a close match does not necessarily mean that other models would not work equally well or better.
%0 Computer Program %A Gallis, Michael %D October 27, 2008 %T Energizer Model %E Christian, Wolfgang %8 October 27, 2008 %U http://www.compadre.org/Repository/document/ServeFile.cfm?ID=8227&DocID=871
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