Although Bloom's Taxonomy was first designed in 1956 as a guide for writing instructional objectives it is still a very valuable model for considering thinking skills and is a useful guide for checking whether students' thinking is being extended to a higher level. There are six levels of thinking in the model.

Six levels of Bloom's Taxonomy

Knowledge:
Comprehension:
Application:
Analysis:
Synthesis:
Evaluation:

The following links provide further information about Bloom's taxonomy.

http://officeport.com/edu/blooms.htm
In 1956, Benjamin Bloom headed a group of educational psychologists who developed a classification of levels of intellectual behavior important in learning. Bloom found that over 95 % of the test questions students encounter require them to think only at the lowest possible level...the recall of information. Bloom identified six levels within the cognitive domain, from the simple recall or recognition of facts, as the lowest level, through increasingly more complex and abstract mental levels, to the highest order which is classified as evaluation ...

http://www.stedwards.edu/cte/blooms.htm#levels
A chart showing Bloom's Taxonomy ...

http://www.stedwards.edu/cte/bwheel.htm
Task Oriented Question Construction Wheel Based on Bloom's Taxonomy. ©2001 St. Edward's University Center for Teaching Excellence ...

http://teach.valdosta.edu/whuitt/col/cogsys/bloom.html
Bloom's Taxonomy explained ...

http://www.nwlink.com/~donclark/hrd/bloom.html
There is more than one type of learning. A committee of colleges, led by Benjamin Bloom, identified three domains of educational activities. The three domains are cognitive, affective, and psychomotor ...

http://www.coun.uvic.ca/learn/program/hndouts/bloom.html
Benjamin Bloom created this taxonomy for categorizing level of abstraction of questions that commonly occur in educational settings. The taxonomy provides a useful structure in which to categorize questions ...

http://faculty.washington.edu/krumme/guides/bloom.html
Major Categories in the Taxonomy of Educational Objectives ...

http://www.bena.com/ewinters/Bloom.html
Who is this guy, Benjamin Bloom, and why all the fuss about his Taxonomy? ...

http://www.kcmetro.cc.mo.us/longview/ctac/blooms.htm
Bloom's Taxonomy divides the way people learn into three domains. ...