Study Guide
Field 014: Physics
Sample Constructed-Response Assignment
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The following materials contain:
- Test directions for the constructed-response assignment
- A sample constructed-response assignment
- An example of a strong response to the assignment
- The performance characteristics and scoring scale
Test Directions for the Constructed-Response Assignment
This section of the test consists of one constructed-response assignment. You will be asked to prepare a written response of approximately 300 to 600 words on the assigned topic.
Read the assignment carefully before you begin your response. Think about how you will organize your response. You may use the erasable sheet(s) to make notes, write an outline, or otherwise prepare your response. start bold and italics However, your final response to the assignment must be either: end bold and italics
- typed into the on-screen response box,
- written on a response sheet and scanned using the scanner provided at your workstation, or
- provided using both the on-screen response box (for typed text) and a response sheet (for calculations or drawings) that you will scan using the scanner provided at your workstation.
start bold Instructions for scanning your response sheet(s) are available by clicking the "Scanning Help" button at the top of the screen. end bold
As a whole, your response must demonstrate an understanding of the knowledge and skills of the field. In your response to the assignment, you are expected to demonstrate the depth of your understanding of the content area through your ability to apply your knowledge and skills rather than by merely reciting factual information.
Your responses to the assignments will be evaluated based on the following criteria.
start bold PURPOSE: end bold the extent to which the response achieves the purpose of the assignment
start bold SUBJECT KNOWLEDGE: end bold appropriateness and accuracy in the application of subject knowledge
start bold SUPPORT: end bold quality and relevance of supporting evidence
start bold RATIONALE: end bold soundness of argument and degree of understanding of the subject areaThe constructed-response assignment is intended to assess subject matter knowledge and skills, not writing ability. However, your response must be communicated clearly enough to permit valid judgment of the scoring criteria. Your response should be written for an audience of educators in this field. The final version of your response should conform to the conventions of edited American English. Your response must be your original work, written in your own words, and not copied or paraphrased from some other work.
Be sure to write about the assigned topic. Remember to review your work and make any changes you think will improve your response.
Any time spent responding to the assignment, including scanning the response sheet(s), is part of your testing time. Monitor your time carefully. When your testing time expires, a pop-up message will appear on-screen indicating the conclusion of your test session. Only response sheets that are scanned before you end your test or before time has expired will be scored. Any response sheet that is not scanned before testing ends will start uppercase NOT end uppercase be scored.
Sample Constructed-Response Assignment
subarea roman numeral 1
Scientific and Engineering Processes
start bold Use the information below to complete the exercise that follows. end bold
A lab team of four students in a physics class is designing an experiment to determine the relationship between voltage and current in a simple circuit. The group's design is given below.
start bold Experiment to Determine Relationship Between Voltage and Current in a Simple Circuit end bold
start underline Materials end underline
- Variable (0–15 V) DC power supply
- Ammeter
- Voltmeter
- 2 resistors
- Connecting wires
start underline Procedure end underline
- Wire the circuit as shown below, with the 100 ohm resistor. There is a diagram of a circuit with a D C power supply, a voltmeter, and an ammeter. The positive terminal of the power supply is connected to the negative terminal of the voltmeter, and the positive terminal of the voltmeter is connected to the negative terminal of the ammeter, and the positive terminal of the ammeter is connected to the negative terminal of the power supply. A resistor is wired between the wire connecting the voltmeter to the ammeter and the wire connecting the ammeter to the power supply.
- Adjust the power supply so that the voltmeter reads 2 V.
- Read the ammeter and record the current and the voltage in a data table.
- Replace the 100 ohm resistor with the 150 ohm resistor.
- Repeat steps 2 and 3.
start underline Data Analysis end underline
Put data in a table and look for a pattern.
- Identify two significant weaknesses in the proposed experimental design and explain why they are weaknesses, from a scientific perspective.
- Describe two modifications that should be made to the experiment and discuss how they address these weaknesses and enhance the scientific validity of the investigation.
- Describe an effective way to analyze and report the data and discuss why this way is effective.
Sample Strong Response to the Constructed-Response Assignment
start bold Please note: The sample response provided below is for review purposes only and should not be used in a response on an operational exam. Use of the exact words and phrases presented in this sample response will result in a score of "U" (Unscorable) due to lack of original work. end bold
The first significant weakness is that the voltmeter and ammeter are not used correctly. Not only are the polarities reversed, the voltmeter is wired in series with the circuit and the ammeter is wired in parallel. This is opposite to how the meters should be used. If the two meters are used in this way, the data will not be valid. It is also very likely that the ammeter will be damaged, since ammeters are very sensitive to current.
The second significant weakness in the design is the failure to measure the correct variables in the experiment. The purpose of the experiment is to determine the relationship between voltage and current in a simple circuit. However, as designed, the experiment fixes the value of the voltage at 2 volts, varies the resistance, and measures the resulting current. Hence, the experiment is measuring how current varies with resistance instead of how the current varies with voltage. In addition, only two data points are being collected. This is too few data points from which to draw any kind of reliable conclusion.
The first modification I would make would be to change the way the two instruments are wired by replacing the ammeter with the voltmeter, and vice versa. In other words, I would wire the ammeter in series to measure the current in the wire. I would next wire the voltmeter in parallel with the resistor to measure the voltage across the resistor. In addition, I would make certain that the polarities of the two instruments are correct. This modification will enhance the scientific validity of the experiment by helping ensure that the data collected is valid.
For the second modification I would make the following changes to the numbered procedures as follows.
- Adjust the power supply so that the voltmeter reads 0 volts.
- Read the ammeter and record the current and the voltage in the data table.
- Increase the voltage by 2 volts.
- Repeat steps 3 and 4 up to 14 volts.
- Replace the 100-ohm resistor with the 150-ohm resistor.
- Repeat steps 2 through 5.
This second modification will enhance the validity of the investigation, because as the voltage is varied, the corresponding current can be measured. In this modification, the voltage is the independent variable, and the current is the dependent variable. It will then be possible to examine the relationship between the voltage and current, which is the goal of the experiment. Repeating the experiment with a different resistor allows students to investigate whether the voltage/current relationship is the same for different values of circuit resistance. In addition, the students will be collecting 8 data points for each resistor, which should more clearly indicate any kind of a relationship in the data.
The data should be reported in two different tables; one table for the 100 ohm resistor, and one table for the 150 ohm resistor. Each table should have columns for voltage and current. These tables should be included in the lab report.
Each table of data should be graphed on an I versus V graph. Students should be able to conclude that the relationship between voltage and current in a simple circuit is linear, i.e., if you double the voltage, you double the current. Further analysis should be done by finding the equation of each line.
Performance Characteristics
The following characteristics guide the scoring of responses to the constructed-response assignment.
Scoring Scale
Scores will be assigned to each response to the constructed-response assignment according to the following scoring scale.