I really like the premise of this questioning method because I feel that it works the students toward higher levels of critical thinking. Here is a brief description of the HRASE hierarchy, as shown by Clough (2007, pg. 1):
History - Ask questions that relate to students' experiences
What did you do when...?
Relationships - Ask questions that have students compare ideas, data, activities, etc.
How does this compare to...?
Application - Ask questions that require students to use knowledge in new contexts
What safety issues could this solve?
Speculation - Ask questions that require thinking beyond the given information
What would happen if you...?
Explanation - Ask questions to get at the underlying reasons or processes
How does that work?
Reference:
Clough, Michael P. (2007). What is so important about asking questions? Iowa Science Teachers Journal, 34, 1.