This document discusses different types of educational technologies including microworlds, simulations, games, and virtual worlds. Microworlds present a simple model of part of the world that students can manipulate to explore alternatives and discover facts. Simulations imitate real processes and allow manipulation. Games incorporate skill, chance, and strategy to simulate reality. Virtual worlds are 3D computer simulations where users take on avatars to interact with others. Examples of each type of technology are provided along with questions to consider about how well they achieve their purpose and how they could be incorporated into classroom learning.