greenfoot: Combining Object Visualisation with Interaction

The introduction of programming education with object-oriented languages slowly migrates down the curriculum and is now often introduced at the high school level. This migration requires teaching tools that are adequate for the intended target audience. In this paper, we present a new tool, named greenfoot, for teaching object-oriented programming aimed at students at or below college level, with special emphasis of supporting school age learners. Greenfoot was designed by analysing and combining the most beneficial aspects of several existing tools. It aims at combining the simplicity and visual appeal of microworlds with much of the flexibility and interaction of BlueJ. To achieve its goals of providing a suitable learners' environment, greenfoot provides a meta-framework that allows easy creation of different, significantly varied microworlds