A claim and evidence is provided. Students have to determine whether or not the evidence supports the claim. They then split into groups and try to write reasoning for the evidence from the perspective that it does support the claim, and then from the perspective that it supports the OPPOSITE of the claim. Students will see why reasoning is important, and how it differs from evidence.
Afterward, to reinforce this idea, students view three pieces of evidence to support a new claim from two different perspectives in terms of reasoning. You throw in an additional piece of 'evidence' (it actually isn't truly evidence) and have students brainstorm reasoning for it from both perspectives! This false evidence will give you an opportunity to touch on how students often include 'evidence' that doesn't actually relate to, or support, the claim. This activity will take about 30 minutes, but is powerful, and you all are likely to enjoy a few laughs.