For each performance assessment in the PALM library, information on the rubrics and scoring is shown on the Rubrics page. When adapting the rubric for a task, you will need to examine this page. The text below shows a sample adaptation of the Rubric for the "Velocity" performance task.

Red text shows modified or added text.

Velocity
Rubric

Contributed by: Council of Chief State School Officers (CCSSO/SCASS)

Item Description:

This event asks the students to determine the average speed of a toy car as it travels six different distances set up by the student. Three trials are to be done for each distance. The only requirement is the longest distance must be at least three times longer than the shortest distance. Students are asked to record measurements in a data table, complete mathematical calculations and graph their results. The data table helps students to organize their findings. All of the data in the table should be reasonable given the distances selected by each student and the type of car used in the trials. Similarly, graphs should present accurate data with appropriately labeled axes. Although students are guided to think about how to appropriately label the axes, teachers should make the decision about how much scaffolding is needed.

Question 1 asks the students to explain why their data may be more accurate for long distances or for short distances. The question is attempting to help the students see that in a very short distance the accuracy of their measurements was limited by the short time interval. If they had difficulty starting and stopping the stopwatch over the specified distance they were actually measuring the instantaneous speed rather than the average speed.

A good response will show the student can interpret the results they obtained. The speed of the toy car should have been approximately the same for the three trials at the longer distances than it was at the shorter distances. The precision of their instruments may also have limited their ability to measure the time over a very short distance.

Question 2 asks students to use their data to describe the relationship between distance and time. Given that the car travels at approximately the same speed for each distance traveled, the car should take longer to travel greater distances.

Question 2  Question 3 asks the students to describe an experiment to determine if cars that pass by the school are speeding. The question is really asking them to apply the concept they learned and used in the experiment, that the average speed of an object is the distance traveled divided by the time it takes to travel this distance.

A good response will show the student can apply this concept to an actual situation. The experiment should include measurement of the distance between two points that the car will pass by and a method to determine the time it takes to travel that distance.
Comment: Many students answered question 2 question 3 by stating a policeman should use a radar gun to see which cars are speeding. To eliminate this problem, the question could have begun with "You are given a stop watch and a measuring tape."

Original Rubric

Summary Table

Criterion

Rubric:
Criterion 1:
It is stated that the data is more accurate for long distances with or without an explanation.

OR

it is stated the data is more accurate for short distances with an explanation that is based on problems with the experimental design. (Q1)
For example:
a. Short because the car spins and turns over long distances.
b. Short because the car didn't travel in a straight line all the time.
The following do not meet this criterion:
a. Short because we could time it better.
b. Short because the car would slow down when it went far.

Criterion 2:
An experiment of some type is described to determine if cars passing the school are speeding. (Q2)
For example:
a. Use a radar gun from the police.
b. Drive a car by at 25 mph and see how many cars pass it.

Criterion 3:
The experiment includes at least one of the following: (question 2)
A. The experiment includes measurement of time.
B. The experiment includes setting up a distance to observe the cars traveling by the school.
C. The student recognizes that to achieve more accurate results the experiment should be repeated (more than one car must be observed).

Criterion 4:
Both of the following are met (from criteria 3):
A. The experiment includes measurement of time (question 2).
B. The experiment includes setting up a distance to observe the cars traveling by the school (question 2).

AND

C. The student recognizes that to achieve more accurate results the experiment should be repeated (more than one car must be observed. (question 2).

OR

D. The student stated and explained in question 1 why longer distances increased the accuracy of their experiment.
For example:
a. There is more room if you make an error if you use a longer distance.
b. The watch we used only could measure in seconds and for some short distances it looked like 1.5 seconds. So the data is more accurate for long distances (or any response that addresses precision of the measurement tools).

Modified Rubric (text included from original rubric is in black font)

Scoring the Data Table (Total possible points: 3)
Student is scored on the quality of their data gathering.
(1 point) Records 3 times at each distance.
(1 point) Trend in time is reasonable given distances selected by the student and type of car used by the student. (Longer the distance the greater the time. Times will vary more for short distances than for longer distances.)
(1 point) Student correctly calculates average time for each distance traveled by the car.

Scoring Graph 1 (Distance x Time) (Total possible points: 3)
Student is scored on the quality of their graphing skills.
(1 point) Axes are appropriately labeled. Distance is on x-axis and time is on y-axis.
(1 point) Student uses appropriate units (distance = cm, time = sec).
(1 point) Data in graph reflects information in the data table.

Scoring Graph 2 (Distance x Speed) (Total possible points: 3)
Student is scored on the quality of their graphing skills.
(1 point) Axes are appropriately labeled. Distance is on x-axis and speed is on y-axis.
(1 point) Student uses appropriate units (distance = cm, speed = cm/sec).
(1 point) Data in graph reflects information in the data table.

Item 1 (Highest possible score = 3)
(Score = 3) Student states that the data is more accurate for long distances with a reasonable explanation.
For example:
a. Long because we had difficulty starting and stopping the stopwatch.
b. Long because we were measuring the instantaneous speed rather than the average speed at the shorter distances.

(Score = 3) Student states that the data is more accurate for short distances with a reasonable explanation.
The following are examples of level 3 responses:
a. Short because the car spins and turns over long distances.
b. Short because the car didn't travel in a straight line all the time.

The following are examples of responses that would not receive a score of 3:
a. Short because we could time it better.
b. Short because the car would slow down when it went far.

(Score = 2) Student states that the data is more accurate for long distances without an explanation.

(Score = 1) Student states that the data is more accurate for short distances without an explanation.

Item 2 (Highest possible score = 3)
(Score = 3) Student states relationship between time and distance that matches their data and provides an incomplete or partial explanation.
For example:
a. As distance increases, time increases because the car is traveling at about the same speed as it goes farther.

(Score = 2) Student states relationship between time and distance that matches their data and does not provide an explanation or provides incomplete/partial explanation.
For example:
a. As distance increases, time increases because my graph shows it.

(Score = 1) Student states relationship between time and distance that does not match data.

Item 3 (Highest possible score = 4)
(Score = 4) The experiment includes all of the following.
a. measurement of time
b. setting up a distance to observe the cars traveling by the school.
c. The student recognizes that to achieve more accurate results the experiment should be repeated (more than one car must be observed.

(Score = 3) The experiment includes at least two of the following:
a. measurement of time.
b. setting up a distance to observe the cars traveling by the school.
c. The student recognizes that to achieve more accurate results the experiment should be repeated (more than one car must be observed).

(Score = 2) The experiment includes at least one of the following:
a. measurement of time.
b. setting up a distance to observe the cars traveling by the school.
c. The student recognizes that to achieve more accurate results the experiment should be repeated (more than one car must be observed).

(Score = 1) An experiment of some type is described to determine if cars passing the school are speeding.
For example:
a. Use a radar gun from the police.
b. Drive a car by at 25 mph and see how many cars pass it.

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