CER

Claim, Evidence, Reasoning

Adapted from Tracy Schloemer, Kirstin Milks, and Stephen Traphagen

Example of a Rubric

Sample Lab Conclusions are veryinformative of student ideas...

From my data, I found that there are 1.29 Calories per gram of the potato chip; however, from thefood label, there is 4.3 Calories per gram. My experimental evidence of Calories per gram was alot less than the nutritional label. This is because I lost a lot of energy in my system to thesurroundings. The hot fry has a larger amount of calories per gram than any of the other foods wetested in both my calculations and the actual amount taken from the food label. I do not believethat we transferred all of the energy from the burnt chip to the water because there were still airparticles around our system and some of the energy could have been transferred to those. Thismeans that instead of heating up the water, it heated up the air around the burning food. I thinkthe reason that there was more energy released per gram of the potato chip as opposed to themarshmallow is because it was impossible to fully burn the marshmallow because it is reallydense. We really only burned the first layer of the marshmallow as opposed to the whole thing.Some sources of error are, it wasn’t a closed system because there were still multiple surroundingsthe system could effect. Also, because the black stuff at the bottom of the can after burning thefood is carbon lost from the food which means we lost some of the mass we needed to measure atthe end, making the mass burned inaccurate. Another source of error is not being able to fully burnthe food. Like the marshmallow, we couldn’t completely burn the entire piece of food because thetongs were in the way.