PALS - Rubric

8th Grade Performance Task
Contributed by: RAND
Designed by: University of California, Santa Barbara, Stanford University, and The Far West Laboratory

VINEGAR DISCOVERY SCORING RUBRIC

PART 1

1a	1 pt	Orange
1b	1 pt	Purple

PART 2

2a	1 pt	Color change in right direction: Purple to Blue to Green to Yellow to Orange to Red; Purple to Red; right to left on color guide; dark to light to dark / got lighter then darker; base to acid colors; colors go in opposite order on universal color guide. Answers must include a start point color and an endpoint. (Not acceptable: Colors became lighter, darker, brighter, bolder, different, light to dark, or dark to light).
	1 pt	Acidity change: base to acid; high to low pH; right to left on color guide; or solution neutralized and then turned to acid. Answers must include a start point (pH or base) and an endpoint (pH or acid).
		Note on 2a: If start point and endpoint are in different measures but are correct (e.g. solution went from Purple to Acid) give 1 point overall for 2a.
2b		DO NOT SCORE (the solution may go from yellowish-green to orange with a single drop)
2c	1 pt	Colors change faster; get to a specific color faster or with fewer drops; final color would be closer to red; fewer in between colors or skipped colors. (Not acceptable: colors are different, brighter, lighter, darker, more intense, bolder; solutions are stronger or weaker; less colors or fewer colors.)
	1 pt	Solutions would be more acidic; become acidic faster; the base will be neutralized quicker/with fewer drops of acid; solution balanced out quicker; end up with a strong or stronger acid.

PART 3

3a	1 pt	Clearly labeled place for recording data for Acids B & C. (Must say B & C: cannot say 1 & 2 or other labels.)
	1 pt	Identifies number of drops for each Acid used or to be used. (Requires 2 tables but they do not have to be labeled Acid B & C respectively.)
	1 pt	Recorded color sequence for Acid B that goes from Base to Acid, e.g. Blue - Green - Yellow - Orange (May be missing only 1 entry at most to receive a point: May use pH numbers instead of colors. No point if obvious no Base X used, e.g. first color shows an acid solution: No point if reversed color interval). Use 3 color rule from Part 2.
	1 pt	Recorded color sequence for Acid C that goes from Base to Acid, e.g. Blue - Green - Yellow - Orange (May be missing only 1 entry at most to receive a point: may use pH numbers instead of colors. No point if clear no Base X used, e.g. first color shows an acid solution: no point if reversed color interval). Use 3 color rule from Part 2.
	1 pt	Color change to neutral (or from base to acid) occurs more quickly for Acid B
		Addressing Unlabeled or Wrongly Labeled Tables or Charts
	1.	If tables labeled for Acids A and (B or C) then two point maximum: 1 point for number of drops and 1 point for correct color sequence for Acid B or C.
	2.	If 1 table labeled correctly (Acid B or C) and 1 table unlabeled then assume unlabeled table is labeled correctly with missing Acid. But penalty of 1 point: do not give point for clearly labeled place.
	3.	If both tables unlabeled or 1 table labeled Acid A and one table blank then 1 point maximum: 1 point possible for identifies number of drops.
		Special Case for 3a
	5 pt	A bar chart, correctly labeled for the two acids and drops used, that shows how many drops to a specific color or pH.
3b	1 pt	Use a clean cup (if mentioned at least once: must specifically say "clean cup," "new cup" or "cup 2"
	1 pt	Fixed amount of Base X used
	1 pt	Indicator used
	1 pt	Same amount of acid added at a time (e.g. 1 drop)
	1 pt	Swirl solution in cup (if mentioned at least once: can also say mix, stir, or shake).
	1 pt	Color recorded after each drop. In place of color, student can also say pH, data, results, findings, or information. In place of recorded, student can also say written or noted (not acceptable is any verb that does not imply writing results down such as observed or watched).
	1 pt	Same procedure done for both Acid B & C (Does not need to be correct procedure to earn this point).
	1 pt	Compare results for the two acids; note difference in outcomes such as number of drops of acid to get to neutral or a specific color or a specific pH level or note speed of color change or shift in pH level; note which acid is stronger.
		NOTE: Scorers cannot refer back to 3a when scoring 3b unless student refers them back to 3a. If no answer in 3b but student has written one in 3a, student must tell reader to refer back to 3a to get points for 3b.
		Special Case for 3b
	4 pt	Answer says to "repeat the same steps done with Acid A in Part 2 but using Acids B & C." Award 4 points overall for 3b. (Give credit only if 2 points earned for Table 1.) If student has developed any other experiment that makes sense, give 4 points.
	1 pt	Compare results for the two acids; note difference in outcomes such as number of drops of acid to get to neutral or a specific color or a specific pH level or note speed of color change or shift in pH level; note which acid is stronger.

PART 4 (4d to 4f are to be scored separately)

4a
	Line 1
	1 pt	Amount of Base X equals 7 or amount noted in 3a or 3b. (What student has written in 3a or 3b takes precedence: if differs from 7 then 7 is not acceptable.)
	1 pt	Number of drops of Acid B noted in 3a or 3b that made solution neutral. (If neutral, yellowish green, not obtained in experiment, OK to interpolate number of drops or use number of drops that get to first acidic color, e.g. yellow or orange. Use first entry on table where change from base to acid occurs.)
	Line 2
	1 pt	Amount of Base X equals 7 or amount noted in 3a or 3b. (What student has written in 3a or 3b takes precedence: if differs from 7 then 7 is not acceptable.)
	1 pt	Number of drops of Acid C noted in 3a or 3b that made solution neutral. (If neutral, yellowish green, not obtained in experiment, OK to interpolate number of drops or use number of drops that get to first acidic color, e.g. yellow or orange. Use first entry on table where change from base to acid occurs.)
4b	1pt	Acid B (Must get 4b correct to receive points for 4c)
4c	1 pt	Fewer drops of Acid B to get to neutral or to get to a specific color or to go from 1 color to another; Acid B changes colors more quickly; Acid B worked faster; Acid B got to a stronger acid color.
4di	1pt	3 vinegars used (may state 3 vinegars used or say each, every, all vinegars): or 2 vinegars (including the unknown) used. The unknown may be called the mystery vinegar or the third bottle.
4dii		These 2 points can be given regardless of validity of experiment
	1 pt	Indicator used
	1 pt	Base X use
4diii		These 2 points are only given if scorer can infer that the unknown vinegar is used. Inference rule is that student says more than 1 vinegar is being tested but does not indicate that only the 2 known vinegars are being tested.
		Also, these 2 points can be given (if the above inference met) if the student sets up a reversed experiment using a set amount of the vinegars and monitors drops of Base X added to the vinegars. Substitute vinegar for Base X and Base X for vinegar in the rubric to score this experiment for the following 2 points.
	1 pt	Amount of Base X held constant in all tests
	1 pt	The amount of vinegar added is monitored (Must use Base X to get this point)
4div	1 pt	A comparison of the results from the different vinegars tested is made. The student must either say: 1. Compare the results of all three vinegars, or 2. Compare the results of the unknown vinegar (may be inferred unknown - see 4diii) with a specific known vinegar (either the 5% or the 6% vinegar). (The comparison must be of the color change to receive this point).
		Special Case for 4d (4 points possible)
	3 pt	The answers says to follow the same steps as in Part 3 and notes that at least 2 vinegars are used (including the unknown vinegar) in place of Acids A & B. (Must get all 5 points on 3a in Recipe or Discovery to get these points. If Text version can get all these points by referring to Tony's experiment as long as use of vinegar discussed).
	1 pt	A comparison of the results from the different vinegars tested is made (see 4iv on the comparison).
4e	1 pt	Base Z or yellow or the illustration of Base Z is circled. (Give point if 4e left blank for 4f has Base Z).
4f	1 pt	Yellow is less acidic or weaker than red; Red is more acidic or stronger than yellow. Takes more drops of Acid to make Base Z acidic; it is less acidic after the same number of drops added; harder to make Base Z an acid; less of a color change means a stronger base; Base Z did not weaker as much as Base Y: the higher pH number is a sign that Base Z is stronger: the resulting solution is closer to a base. (Must get a point for 4e to receive this point)
	1 pt	Number of drops of the bases and acids held constant for both tests (only needs to be said once).