• CER (Claim-Evidence-Reasoning) graphic organizers
• Moon phase observation data (images or charts)
• Scientific explanations reference sheet
• Sentence starters for each CER component
• Moon phase simulation or model materials
• Peer review checklist
• Sample CER responses of varying quality

Prepare moon phase observation data spanning a month. Create a CER graphic organizer with sections for each component. Develop a reference sheet explaining the difference between evidence and reasoning. Gather examples of strong scientific explanations.

1. Introduce the CER framework as a method scientists use to explain phenomena:
2. Claim: A statement that answers the question or explains the phenomenon
3. Evidence: Scientific data that supports the claim
4. Reasoning: Explanation connecting the evidence to the claim using scientific principles
2. Model the process using a simple example unrelated to the moon:
3. Question: 'Why do ice cubes melt faster in warm water than in cold water?'
4. Claim: 'The temperature of water affects how quickly ice melts.'
5. Evidence: 'In our experiment, ice in 80°F water melted in 3 minutes, while ice in 40°F water took 12 minutes to melt.'
6. Reasoning: 'When water molecules have more thermal energy (higher temperature), they collide with the ice more energetically, transferring heat faster and breaking the solid bonds in the ice more quickly.'
3. Present the moon phase investigation question: 'What causes the moon to appear to change shape throughout the month?'
4. Evidence collection (10-15 minutes):
5. Students analyze moon phase observation data
6. Use moon phase models or simulations to investigate the Earth-Moon-Sun system
7. Record relevant data and observations
5. Individual CER development (15 minutes):
6. Students write a claim about what causes moon phases
7. List specific evidence from observations and simulations
8. Develop reasoning that connects evidence to their claim using scientific principles about light, shadows, and the Earth-Moon-Sun relationship
6. Peer review process (10 minutes):
7. Partners exchange CER responses
8. Use checklist to evaluate strength of each component
9. Provide specific feedback for improvement
7. Revision and finalization (10 minutes):
8. Students revise their CER based on feedback
9. Ensure reasoning clearly connects evidence to claim
10. Add diagrams if helpful for explanation
8. Class discussion: Compare different approaches to reasoning and discuss how the same evidence can be used to support claims.

For struggling students, provide sentence frames for each CER component. For English learners, allow drawing and labeling to supplement written responses. For advanced students, challenge them to address counter-arguments or alternative explanations.

Evaluate completed CER responses using a rubric that assesses accuracy of claim, relevance and specificity of evidence, and depth of reasoning. Note common misconceptions about moon phases to address in future lessons.