CER Claim Evidence and Reasoning A framework for

CER: Claim, Evidence, and Reasoning A framework for constructing scientific explanations.

Start with a question Are fat and soap the same substance or different substances?

What is a claim? A statement that expresses the answer or conclusion to a question or problem.

How do I write a claim? ● I accept (or reject) my hypothesis that (reword hypothesis) because. . . OR ● Write a scientific explanation that answers the scientific question.

Claim Example Question - Are fat and soap the same substance or different substances? Claim - Fat and soap are different substances.

Evidence Table 1. 1 - Student Data Collection for Fat and Soap Color Hardness Solubility Melting Point Fat Off-white or slightly yellow Soft-Squishy Water - no, Oil ~ 37 ℃ - yes Soap Milky White Hard Water - yes, Oil - no Higher than 100 ℃

What is evidence? Scientific data that supports the claim. This can come from measurements, observations, and results. It needs to be appropriate and sufficient.

How do I write evidence? ● ● ● Use observations you have gathered Use averages when you have multiple trials Report high number Report low number Report high - low = difference Explain any outliers

Evidence Example Fat is off-white and soap is milky white. Fat is soft and squishy and soap is hard. Fat is soluble in oil, but soap is not soluble in oil. Soap is soluble in water, but fat is not. Fat has a melting point of ~37 ℃ and soap has a melting point above 100 ℃.

What is reasoning? This explains why the evidence was collected and how it supports the claim. Provides a logical connection between evidence and claim. This is the BIG science idea behind the question.

How do I write reasoning? ● Explain WHY you accept or reject your original hypothesis ● Support your explanation with 2 -3 sentences ● Incorporate one or more scientific principles to explain your results (Big Science Idea) ● Make inferences

Reasoning Example Fat and soap have different physical properties and therefore are different substances.

Putting it all together. . . Fat and soap are different substances. Fat is off-white and soap is milky white. Fat is soft and squishy and soap is hard. Fat is soluble in oil, but soap is not soluble in oil. Soap is soluble in water, but fat is not. Fat has a melting point of ~37 ℃ and soap has a melting point above 100 ℃. These are physical properties. Because fat and soap have different properties, they are different substances.

Non-Example “Fat and soap are both stuff, but they are different substances. Fat is used for cooking and soap is used for washing. They are both things we use everyday. The data table is my evidence that they are different substances. Stuff can be different substances if you have the right data to show it. ”

Now you try. . . Question: Who is the greatest quarterback of all time? Number of Receptions/Pass Completions Number of Touchdowns Interceptions Sacks Super Bowl Wins Russell Wilson 1490 127 45 208 1 Tom Brady 5260 456 152 420 5 Table 1. 2 - NFL data collection for Russell Wilson and Tom Brady