# Sample C-E-R

Claim-Evidence-Reasoning (CER) Rubric

Examples:

Claim-- Recess is good for kids' health.
Evidence-- A 2008 study demonstrated that kids' heart rate imporoved after 30 minutes of recess per day when compared to students who did not have recess.
Reasoning-- Because the evidence shows that kids' heart rate imporved after 30 minutes of recess when compared to students who did not have recess, we know that recess is good for kids' health.

Claim-- Oreos are the most popular cookie at my house.
Evidence-- My family buys two types of cookies: Oreos and Snickerdoodles.  Each type comes 20 in a box.  Oreos run out twice as fast as Snickerdoodles.
Reasoning-- Because my family eats twice as many Oreos as Snickerdoodles, I know that Oreo is the most popular cookie type at my house.

Topic: Continental Drift
Problem:
Does the rock and fossil evidence support Alfred Wegener's theory or continental drift?
Conclusion:
Claim-- The rock and fossil evidence found on all the continents supports Wegener's theory of continental drift.
Evidence-- Wegener noticed that South America and Africa appear like they could fit like puzzle pieces and he found that there look-alike animal and plant fossils and similar rock formations found on different continents.
Reasoning-- The Earth's continents were once joined but have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed.

Topic: Fermentation
Problem:
What is a product of cellular respiration?
Conclusion:
Claim--Yeast produces carbon dioxide (CO2) during cellular respiration.
Evidence--When the yeast mixed with the sugar water, the indicator BTB turned from blue to yellow. This means that CO2 was present.
Reasoning-- The yeast ate the sugar and metabolized it.  It used the glucose in the sugar water solution and produced CO2 gas as a waste product.  Yeast breaks down sugars in a process called alcoholic fermentation.  When this happens alcohol is produced. On page 94 it says, "The other products are carbon dioxide and a small amount of energy."

Topic: Sedimentary Rocks
Problem:
Coral reacts to acid the same way limestone and coquina do.  What could you conclude about the mineral composition of coral?
Conclusion:
Claim--Both the limestone and coquina have calcite in them and react to an acid.  A piece of coral reacts to acid the same way. Coral is also made out of calcite.
Evidence--Coquina is a rock consisting of loosely cemented shell fragments.  The limestone sample was denser and well cemented. The dilute acid fizzed on both samples.
Reasoning--Limestone forms when calcite in water comes out of solution and forms crystals which turn into limestone rock.  Coquina is made up of shells that are made up of a lot of calcium too.  On page 108 it says, "Coral animals form their skeletons by absorbing the element calcium from the ocean water.  The calcium is then combined with carbon and oxygen to form the mineral calcite."

Topic: Radioactivity
Problem:
What is the half life of Penninium (Pe)?
Conclusion:
Claim--The half life of Pe is 15 seconds.
Evidence--Every 15 seconds half of the original amount was remaining and did not decay. In my graph the relationship varied inversely.
Reasoning--  Half life is the amount of time it takes for half of a sample to decay.  On page 139 it says, "In the process called radioactive decay, the atomic nuclei of unstable isotopes release fast-moving particles and energy."  While the radioactive decay varies widely depending on the element, every radioisotope has a characteristic half life.  We simulated radioactive decay with the random process of the coin toss.