Destined for use in project-based science classes, it took 4 years to develop the Model-It™ software and bring it at a point that it can successfully fulfill the design and learning goals. The design goals that guided the course of the software remained the same throughout all the development stages (Jackson, Krajcik, Soloway, 2000, in Jacobson, & Kozma, 2000).

The researchers’ goals were to design a tool that:

• is learnable by middle and high school students
  
• allows them to easily construct models of dynamic systems
• build and test models of their own design, to represent and explore their understanding of the phenomena under study

The researchers/designers evaluated the software according to how easy it was for students to begin constructing models and remain engaged, as well as according to whether is supported diverse populations of learners in different learning situations.

Version 1: “Modeler 1.0” (1994)
Modeler 1.0 was developed in 1994 and the main focus was its functionality (Figure 1). By 1996, the Object Editor was added, providing the functionality of creating new objects in the software. The next feature added was the map view. Within the first two years of its development, the software afforded the basic features, as well as run-time graphs showing the changes in the objects over time.

Version 2: “Model-IT 2.1” (1996)
In version 2 there were two major design changes that altered the feel of the software. The whole interface was redesigned and the object window was not being used anymore, and therefore, it was downplayed. That was replaced by a new Object button. Also, the Object Editor was inserted, contributing to the consistency of the factor and relationship editors, and the map view was mainly focusing on the designing of models and their testing.

Version 3: “Model-IT 3.0” (1996-1997)
Within the same year there had been significant redesign changes related to scaffolding practices. A few layers of scaffolding were added, aiming to break down the complexity of the modeling process. Scaffolding was fadeable, so that, as students’ thinking was becoming more complex, the process would become more challenging, accessing advanced functionality. In this latest version there were new window features added to scaffold learning around scientific modeling and reflection on personal creations (Jackson, Krajcik, Soloway, 2000, in Jacobson, & Kozma, 2000, p. 82). The Help window (Figure 3c) and Notepad (Figure 3a) were added to help students with note taking and operation the software. The new tasks after this modification included planning of the model before developing it, as well as evaluating it; a new kind of support for testing and debugging (Figure 3b).

Figure 3a: The Notepad tool

Figure 3b: Running the simulation Figure 3c: The Help window

 

The most radical changes of the software are manly visible in the third version, where there are colorful representations, and more sophisticated tools.