Scaffolding — Physical versus Instructional
In the physical world, scaffolding includes structures that help people do tasks that are not possible without some form of support. For example, in order to clean upper level windows on a high rise building, humans need to be physically placed in close proximity with the windows.
Instructional scaffolding is a metaphor that translates the notion of physical scaffolding into a form of cognitive scaffolding. The two have one similarity—both help people do tasks that cannot be accomplished without them. That’s where the similarity ends.
To summarize the difference:
Physical scaffolding must be in place for the task–(one cannot wash windows on a high rise building without some form of scaffolding) whereas Instructional Scaffolding to support Cognition is temporary (for a particular task or performance)–when the learner becomes better able to independently accomplish the task, the support is removed.