Score Level 1 Anchor Paper

This response shows some understanding of the question. The student identifies water quality (pollution) as a variable that might affect the outcome of the experiment and then gives an explanation that is vague (because the fish would not grow as much as normal). Supporting details for a way to redesign the experiment (use more fish) are only minimally effective (to see if the data would stay the same). There is no explanation as to why such a modification would lead to more reliable data. What the student calls a "hypothesis" (the effect of water tempature on the growth of fish) is mostly a rewording of the prompt, not the predicted outcome of an experiment. An actual hypothesis, in this case, would relate the difference in water temperature to an expected change, more specifically, an increase or decrease in growth rate.

Score Level 1 Anchor Paper

This response provides evidence of some understanding of the question. The hypothesis (the change temperature affected the growth of fish) is general in that it does not specify an increase or decrease in the predicted growth rate due to the temperature difference. The explanation of how the data might support this hypothesis (because the warmer the water the smaller they were) is incorrect in that it addresses only the mass of the fish, not the growth rate. The student identifies one variable that might affect the outcome (starting mass) but provides only a minimal description (if ones mass is larger… than it will have a larger mass at the end). Controlling this variable is listed as a suggested redesign, but the explanation is vague (so you could tell whether the temperature affects the growth).

Score Level 2 Anchor Paper

This response demonstrates a basic understanding of the question. The student states a hypothesis (the fish would grow larger in warmer temperatures) that can be tested in a specific experiment. The two growth rates in the chart are compared (113%; only 34%) to show that the results support this hypothesis. The student identifies several variables (size of the tank, where it was located and if both fish were equally healthy), and makes a few suggestions for designing a better controlled experiment (add more fish with different temperatures; all of the fish start with the same mass). Supporting details are adequate.

Score Level 2 Anchor Paper

This response provides evidence of a basic understanding of the question. The hypothesis (The warmer the water, the more the fish will grow) is adequate. The student suggests several variables related to the fish (starting mass; health; age; type), and suggestions for designing a better controlled experiment (a control; tested more fish; more varying temperatures) are given. Overall, the listing of several variables and suggestions constitutes adequate development of the response to those aspects of the question.

Score Level 2 Anchor Paper

This response shows a basic understanding of the question. The hypothesis (if they put the fish in warmer water than the fish will grow faster) is adequate. The student compares the two growth rates in the chart (grew 113% in warm water and 34% in normal water) to show that the results support this hypothesis. The suggestions for redesign simply involve keeping the listed variables constant (amount of light; pH level; habitat size). Supporting details are adequate. More development would be needed for a higher score.

Score Level 3 Anchor Paper

This response shows a good understanding of the question. The hypothesis is clear (if a fish is put in warmer water, then it will grow faster), but the student only describes the results in general terms (the warm-water fish grew more, percent wise, than the cool water fish), without using any specific data. However, the explanation for redesign is quantified (50 cloned fish) and draws on generally complete supporting details about the other variables in the experiment (species; age; health; neither fish was a "dud," meaning a genetic mutant or something unexpected), which shows synthesis of information (the only way to assure no other factors). A reason for increasing the sample size is also provided (the more number of subjects, the more realistic the average of them).

Score Level 3 Anchor Paper

This response demonstrates a good understanding of the question. The hypothesis is very specific (if a species of fish is placed in warmer water [26°C], then it will grow faster than if placed in cooler water [22°C]). The evaluation of that hypothesis compares experimental data at both temperatures (had a 113% increase; had only a 34% increase). The student synthesizes information about other variables (the specific fish used; variation in all populations; more likely to be reliable) to propose specific redesign ideas (several fish; same mass; tanks of the same size). The accurate use of scientific terminology (mean growth rate, variation) strengthens the response.

Score Level 4 Anchor Paper

This response demonstrates a full and complete understanding of the question. Data are analyzed in terms of the hypothesis (warmer water grew 113%; only 34%). There is synthesis of information throughout the response; beginning with the student's reasoning about one of the variables (sizes of the fish from the start). The student reaches strong conclusions in describing this variable (possible that the smaller fish was younger) and the specific way in which it might affect the outcome of the experiment (therefore grew more rapidly; might have reached the end of its growth; couldn't grow as much as the other fish). Finally, by explaining other variables (type of water; had some disorder) in complete terms (might have more nutrients; ate too much or too little), the student integrates the evaluation of the experiment (problem with the initial experimental design) into the redesign suggestions (have many tanks; average the final results; Abnormalities in a fish wouldn't be as much of a problem because of the larger data set.) The accurate use of scientific terminology (abnormalities; larger data set) enhances the response.