Good critical thinking occurs when many facets of an issue or concept are explored. This exploration can be encouraged by separating students in some way based upon their perspectives or opinions and inviting them to explain and advocate for their views. If the topic is not one about which students already have an opinion, the teacher can assign students to a position.
This activity is useful either for smaller classes or for "delegates" to volunteer in a larger class.
If the topic is an emotionally-charged issue, the teacher must be willing to lay clear and firm ground rules about communicating with scholarly respect, to slow the discussion down when it begins to accelerate emotionally, and even to call a halt to discussion if disrespectful discord looms.
We all want students to carry our teachings into their lives. Often, however, we must make our intentions very plain for students to understand that an assignment will equip them with skills and empower them, and is not an arbitrary hoop through which they must jump.
For this reason, frame each activity using these four steps:
Among the most useful things we as teachers can do during class discussion is shut our mouths. In an oft-cited meta-analysis of wait-time research, Tobin (1987) described findings of greater engagement and achievement when teachers waited at least three to five seconds after asking a discussion question before speaking again. Above this threshold, higher level thinking was observed and student academic performance improved. However, teachers behaving "normally" only tend to wait about one second. Students need a few moments to digest what they have recently heard, formulate their responses, and work up the courage to speak. Slow down, and more of your students will keep up with you.
Reference: Tobin, K. (1987). The role of wait time in higher cognitive level learning. Review of Educational Research, 57, 1: 69-95.