Claim-Evidence-Reasoning Format for Lab Write-ups in Chemistry 2014 CLAIM: Answer the question at the beginning of the lab (1 sentence) EVIDENCE: Describe the evidence that supports the claim. Use observations and data (with units) from your lab results. (At least 3 sentences) REASONING: Explain how the evidence that your described supports the claim that you made. This is the “because” section. Often you will need to refer back to basic scientific principles (I.e. “Substances 2 and 4 were the same because they had the same properties. Substances with the same properties are most likely samples of the same substance.”) (At least 3 sentences) ERROR ANALYSIS: Describe results of any error analysis calculations: 5% rule for y-intercept, % error, etc. Describe at least 2 possible sources of error in the lab. Be specific. ”Human error” and “measurement error” are NOT specific. Think of possible errors in processes you use in lab.