After the brainstorming, I had students try to research my question (Should we teach algebra to high school students?) or claim (high school should start later). They all found an article and tried to evaluate its Credibility, Reliability, Accuracy, and Purpose/Point of View using the CRAP test handout:
That's the idea for today - students will choose their claims and questions and begin researching articles and websites they think they can use. They will fill out the CRAP tests for each one, and if they think they can trust the source, they will start gathering evidence from it to use to prove their claim or to answer their question.
About an hour into class, I'm going to show them how to write an argumentative paragraph to prove a claim. They will then be able to start writing their paragraphs.