1. CER: Claim, Evidence, and Reasoning
A framework for constructing scientific explanations.
Can provide copies of this presentation on paper or electronically.
Make sure students tape copies of CER cheat sheet and CER rubric in their Scientific Notebooks for use all year.

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

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

4. 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.

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

6. 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 - yes
~ 37 ℃
Soap
Milky White
Hard
Water - yes,
Oil - no
Higher than 100 ℃

7. What is evidence? Scientific data that supports the claim.
This can come from measurements, observations, and results.
It needs to be appropriate and sufficient.
Ask students to define appropriate and sufficient in their own words.

8. 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

9. 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 ℃.

10. 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.
This can be the most difficult for students.

11. 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

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

13. 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.
With a partner - identify the different parts (Claim, Evidence, and Reasoning) in this example.

14. 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 take a look at this non-example and discuss with your partner what is wrong with each part of the CER.

15. Now you try... Question: Who is the greatest quarterback of all time?
Table NFL data collection for Russell Wilson and Tom Brady
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
Using the following data, come up with a claim, evidence, and reasoning to answer the provided question.
Have students use a graphic organizer.