The SAMR model is a way of thinking about your use of Technology in the classroom.
It starts with Substitution: i.e. just doing what you would have done anyway, but with technology, then moves through Augmentation and Modification to reach Redefinition.
What does Google Earth allow you to do that would not be possible without it, in an educational context ?
Here's a sheet that you could use to help capture your thoughts and/or discussions.