There are many types of technology/media that can be used in the classroom to enhance instruction. The most common are the overhead projector and PowerPoint presentations. Other types of media are the internet, simulators, graphing calculator software, Geometer's Sketchpad (mathematics), etc.
In my math classroom I use the overhead projector almost daily. I would love to use the computer more frequently for overhead presentations but I would not be able to demonstrate how to solve a problem and write out each step with the class on an application like PowerPoint. I also want to use other types of media because the students have demonstrated reflexive behavior (similar to Pavlov's dog) of tuning me out as soon as I pull the overhead projector to the front of the room. I try to mix things up by alternating between chalkboard, individual whiteboards, group work, worksheets, overhead projector instruction, and interactive games during review. I still feel there is so much opportunity to effectively utilize technology in the classroom that I still have not tapped into.
I am also interested in using technology to simulate abstract mathematical concepts. Some of the textbook publishers now have corresponding websites that have animations of certain topics. I have used some of these animations in my classroom but they were not actual "animations" so much as a series of illustrations so they were not as effective as I had hoped they would be.
According to Heinich, the teacher must carefully select the appropriate type of media that can be used to achieve the specific objective.