Claims, Evidence, Reasoning

1. Claims, Evidence, Reasoning

2. What is it? • In science, an answer you give must be supported with data, and that data must be interpreted. • CER is a logical way to ensure that you answer the question, provide data, and interpret what that data means with respect to the question. • Always answer the question with a claim, evidence, and then reasoning.

3. What are they? • Claim: “A statement or question that answers the original question / problem.” • Evidence: “Scientific data that supports the claim. The data needs to be appropriate and sufficient to support the claim.” • Reasoning: “A justification that connects the evidence to the claim. It shows why the data counts as evidence by using appropriate and sufficient scientific principles.” • Source: http://www.nsta.org/elementaryschool/connections/201104ClaimsEvidenceRubric.pdf

4. Example: • Question: Which of the following is more dense: a ball made of lead, or a ball made of wood having the same volume as the lead ball? • Claim: The lead ball is more dense. • Evidence: The lead ball’s mass 50 g, while the wood ball’s mass is 40 g. • Reasoning: Because the lead ball’s mass is 10 g greater than the wood ball’s mass, and the lead ball must have a greater density.

5. Practice • Identify the following as a claim, evidence, or reasoning: • The 400 g car was displaced 30 cm after the collision, while the 200 g car was displaced 60 cm after the collision. • The heavier the car, the less distance the car will be displaced after colliding with another car. • The two cars moved with the same speed prior to the collision. After colliding, the car with the greater mass was displaced a smaller distance because it takes a greater amount of energy to move a larger mass.