Bloom's taxonomy is a model of the stages and progression of critical thinking. The higher one gets on the pyramid, the higher order of thinking is demanded. The following article suggests what a student should be able to achieve at each level and how teachers can practically scaffold their students' understanding in order to reach the pinnacle of critical thinking. It focuses on practical application of classroom activities and is geared towards slightly older students. It targets grades 7 to 12. However, Bloom's taxonomy can be followed and adapted even at the elementary level.

Identify the steps associated with the critical thinking process. Bloom's Taxonomy is comprised of six categories of critical thinking: knowledge, comprehension, application, analysis, synthesis, and evaluation. Each step requires a higher level of thinking and should be used to meet maximum potential for retention.

Begin with a knowledge base. Common verbs associated with revealing a student's knowledge are to tell, describe, list, state, and name. Knowledge is a basic recall of ideas; it often requires a student to relay the basic who, what, when, where, and why of any given situation. In order to access a student's knowledge, a teacher can ask students to make lists of events, create time-lines, chart facts, list action sequences, describe details, or recite information.

Test comprehension. Students may be able to tell you surface information about a subject, but what do they understand on a deeper level? Can they read between the lines? Teachers may ask students to explain, interpret, discuss, predict, or compare ideas. In order to test comprehension of a given subject, teachers can ask students to create illustrations to retell the story, retell a text in their own words, discuss the main idea or theme of a story, or compare one concept with another in terms of similarities or differences.

Apply knowledge and comprehension to create a tangible result. In order to apply a concept, a student should be able to solve, show, use, construct, examine, or classify knowledge and understanding. Some application of ideas can be illustrated through model building, diagrams, dioramas, scrapbooks, puzzle or game design, and murals. All of these activities encourage a student to take what they know and present their ideas in a non-traditional application. Not only will he be creating a tangible object based on their knowledge, but he should be able to explain its significance to the topic at hand.

Analyze the topic, subject or text. This is the beginning of higher-order thinking; at this point, many students will struggle to make rational sense of their understanding, Therefore, it is essential that analysis be teacher-guided and modeled initially. In order to analyze, a student should be able to distinguish examine, compare, contrast, investigate, connect, and explain her rationale. To reach analysis, a teacher can assign activities that naturally ask for analysis of a subject such as having students create questionnaires, conduct interviews, investigate or research information to support a view or opinion, write a biography, or prepare a report on a chosen topic.

Synthesize ideas. Synthesis is similar to application, but it's on a much more sophisticated level. It requires a complete understanding of a topic in order to create a viable and thought-provoking project. To synthesize, one must first be able to invent, compose, plan, construct, imagine, propose, devise, or formulate. For teachers, this is an in-depth project assignment that may require significant time for students to adequately prepare. Some projects to consider are to invent a machine, design a building, create a new product complete with a name and marketing campaign,write a script for a play, TV show, or film, design an art project to visually capture the subject matter, choreograph a dance, or compose a musical piece related to the topic. Again, these projects are time-consuming and may take several months to see to fruition; they could easily be a culminating final project for a course.

Evaluate understanding. An important step in critical thinking and the most important factor in material retention is to allow students to reflect on their processes: an educational term known as meta-cognition. Evaluating one's understanding requires a person to look outside of herself and involve others in the defense of her ideas. Students, once at this top level of reasoning, should be able to judge, select, choose, justify, debate, verify, argue, recommend, or rate their subject matter as well as their own understanding of it. To allow a student to reach an evaluation of her own work, a teacher should encourage the student to ask questions about the position, solution, belief, and what could be changed and differed. She should ask where she goes from here. Based on these questions, teachers could ask students to stage a debate, write an evaluation, hold a panel discussion, or write a letter inciting change.