The Ejs user interface promotes an integrated understanding of the modeling process by exposing and providing access to the underlying
assumptions in the physical model. The Simple Harmonic Oscillator model is displayed here.
The Ejs user interface promotes an integrated understanding of the modeling process by exposing and providing access to the
underlying
assumptions in the physical model. The Simple Harmonic Oscillator model is displayed here.
The First Law model was built with the Easy Java Simulations (Ejs) modeling tool. Ejs is a Java program that enables both programmers and novices to quickly and easily prototype, test, and distribute packages of Java simulations. It can be downloaded from the Ejs website and installed (unzipped) into a directory of your choice.
An important feature of the programs in the osp_mechanics.jar package is that it was created in such a way that users can return to the Ejs authoring tool at any time to examine, modify, and adapt the Ejs models. Right-click on the green arrow to invoke this feature. (You must, of course, have already downloaded and installed Ejs.) The Ejs authoring tool will appear as shown in the Figure above.
Ejs simplifies the modeling process by breaking it into activities that are
selected using radio buttons as shown in the Figure: (1) documentation, (2) modeling, and (3) interface design. The model's
html-based documentation is accessed by selecting Description. The physics is accessed by selecting Model which
provides access to the data and the methods (Java code) by which the model can change. A plot is a visual representation of
data and is an example of a View. Because it is possible to have multiple views of the same data and because the model
and its views are controlled by buttons and other user interface components, Ejs provides a graphical drag-and-drop editor for
these objects which eliminates much coding. The Ejs model-view-controller
paradigm is well known in computer science and provides a solid foundation for software development.