Study Guide
Field 026: Middle Level Science
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 and weak response to the assignment, and a rationale for each
- 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 are to prepare a written response of approximately 300–600 words on the assigned topic. You should use your time to plan, write, review, and edit your response to the assignment.
Read the assignment carefully before you begin to write. Think about how you will organize your response.
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 merely to recite factual information.
Your response to the assignment will be evaluated on the basis of the following criteria:
start bold PURPOSE: end bold the extent to which the response achieves the purpose of the assignment
start bold SUBJECT MATTER KNOWLEDGE: end bold accuracy and appropriateness in the application of subject matter knowledge
start bold SUPPORT: end bold quality and relevance of supporting details
start bold RATIONALE: end bold soundness of argument and degree of understanding of the subject matterThe 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 written 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. You may not use any reference materials during the test. Remember to review what you have written and make any changes you think will improve your response.
Sample Constructed-Response Assignment
subarea roman numeral 1
Foundations of Scientific Inquiry
start bold Read the information below; then complete the exercise that follows. end bold
A middle level science teacher is preparing an investigation on electricity and magnetism. Students will construct a simple electromagnet, make observations of its properties, and evaluate factors that affect its strength.
Write an essay describing how to carry out this investigation. In your essay:
- describe the materials required for the activity;
- identify the variables that affect the strength of the electromagnet;
- describe an appropriate experimental design for testing one of these variables and show how data from the investigation will be recorded and analyzed; and
- identify two basic physical science concepts that are related to the investigation and explain how the results of the investigation can be used to illustrate these two concepts.
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
Prior to this investigation, students will have had an introduction to magnets, electricity, and electromagnetism. In the investigation, the students will experiment by making an electromagnet out of simple materials.
To make a simple electromagnet requires a 1.5-V battery, a 50-cm length of insulated copper wire, and a large iron nail. The relative strength of electromagnets the students make could be measured by determining how many paperclips their electromagnet can lift. The independent variables that would likely affect the strength of the electromagnet are the length of the wire used to make the coil, the size (e.g., mass) of the iron nail used, and the voltage used to produce a current in the wire. Depending on what independent variable they intend to manipulate, the students would need either a 100-cm length of insulated copper wire, a second 1.5-V battery, or a different size iron nail. Approximately 10 small metal paperclips would be needed to measure the strength of the electromagnet as the students vary the length of the wire, the amount of voltage supplied, or the size/mass of the iron nail.
To test how changing one of the independent variables will affect the strength of their electromagnet, students must first chose the independent variable that will be manipulated during the test. In this example, the wire length will be the manipulated variable. The other independent variables (i.e., the amount of voltage supplied to the circuit and the size/mass of the nail) will be held constant. The dependent variable to be measured would be the number of paperclips the electromagnet can lift with the paperclips being lifted end to end from the tip of the magnified iron nail. With wire length as the independent variable to be changed, the experiment would be designed as follows: First, the control electromagnet is constructed with a 1.5-V battery, a 50-cm length of wire, and the iron nail. The wire is tightly wrapped around the nail (leaving the tip exposed) to create the coil, one end of the wire is attached to the positive battery terminal, and the other end is attached to the negative battery terminal. Since this is now a closed circuit, the wire will heat up and care should be taken in handling the electromagnet. Making sure the coil is still tightly wrapped around the nail, the tip of the iron nail will now be able to lift a few paperclips. The number of paperclips the electromagnet lifts is now recorded. This part of the experiment should be conducted several times to make sure that the electromagnet picks up a consistent number of paperclips during each trial. After this step, the circuit is disconnected and the wire is unwrapped. The new 100-cm section of insulated copper wire is now tightly wrapped around the nail. If the 50-cm wire completely covered most of the nail, the 100-cm section of wire will require a second layer of coils that is wrapped over the first layer of coils. The battery is hooked to the circuit and the experimenter again measures how many paperclips the new electromagnet can lift. As in the first control experiment, this procedure should be repeated several times to accurately determine how many paperclips the electromagnet can lift. The data from both the control experiment and the second experiment can then be compared on a chart or graph.
A basic physical principle involved in this experiment is that the flow of charge (i.e., electric current) through a circuit produces an electromagnetic field. This is the phenomenon that makes electric motors and generators work. Another important principle at work in this simple electromagnet is that the electromagnetic field produced by the current in the wire magnetizes the iron nail even though the wire is insulated and not physically in contact with the nail. This happens because the electromagnetic field generated by the current-carrying wire aligns the iron atoms in the nail in one direction, making the iron nail into a magnet. The nail will retain some magnetic properties for a short while after the circuit is disconnected because of the alignment of the atoms in the nail. Tapping the nail on a hard surface several times will cause it to lose its magnetic properties as the iron atoms will be knocked out of alignment with each other.
Rationale for the Sample Strong Response
Please note that the response is evaluated based upon the four performance characteristics of Purpose, Subject Matter Knowledge, Support, and Rationale. Please also note how the score point descriptions are based upon how the examinee attends to the performance characteristics. You should be very familiar with the CEOE performance characteristics and score scale and refer to them when reviewing this rationale.
The response fulfills the purpose of the assignment (refer to the instructions for the assignment) by completely responding to the four bullet points. The writer specifically identifies what materials are required for the activity (i.e., a 50-cm length of insulated copper wire, a 1.5-V battery, and a large iron nail). The writer accurately identifies electromagnet strength variables (i.e., wire length, nail size, and battery voltage). The writer uses high-quality examples by suggesting metal paper clips be used as objects to measure electromagnetic strength. The writer then demonstrates an accurate application of subject matter knowledge by describing an appropriate experimental design for testing one of these variables. For instance, the writer explains one experimental design by describing how the wire length variable and the method of attachment with tight coils must be repeated several times to accurately determine how many paper clips can be lifted. The writer further supports his or her description by explaining that this process is to be repeated with a 100-cm section of wire. In order to show how the data from the investigation will be recorded, the writer explains that the paperclip numbers from both trials can be "compared on a chart or graph." The writer goes on to demonstrate sound supporting evidence by identifying two accurate and appropriate physical science concepts: "the flow of charge (i.e., electric current) through a circuit produces an electromagnetic field" and "the electromagnetic field produced by the current in the wire magnetizes the iron nail even though the wire is insulated and not physically in contact with the nail." Lastly, the writer gives relevant examples to explain how the activities in the experiment can illustrate the two identified physical science concepts. Overall, the response reflects an ably reasoned, comprehensive understanding of the topic.
Sample Weak Response to the Constructed-Response Assignment
In order for students to understand the concepts of electromagnetism, what a battery produces, how energy travels in a wire, and how the properties of iron change, a brief introduction to electricity and magnetism is necessary.
A simple electromagnet requires a 1.5v C or D sized battery, a length of thin copper wire and an iron nail with some adhesive tape with a sheet of paper, small nail brads, and a small ruler. Wrap about 10 turns of wire around the nail attaching one end of the wire to the base of the battery and the other end to the top end. Placing a few brads on the paper and bring the end of the nail toward the brads slowly noticing the first tiny movement of the brads and measure that distance. Next, bring the nail end close to the brads and see how many brads can be lifted. Add another 10 turns around the nail and repeat the process. Repeat with thirty turns. Record the data.
The basic physical science concept is the behavior of electrical current in a wire. This has caused the iron to turn into a magnet and pick up the brads as can be seen when the iron nail was able to pick up the brads. This occurs only if the battery produces the electrical flow through the wire – more coils leads to more magnetism. With the wire removed from the battery, no magnetism occurred.
Rationale for the Sample Weak Response
Please note that the response is evaluated based upon the four performance characteristics of Purpose, Subject Matter Knowledge, Support, and Rationale. Please also note how the score point descriptions are based upon how the examinee attends to the performance characteristics. You should be very familiar with the CEOE performance characteristics and score scale and refer to them when reviewing this rationale.
The purpose of this assignment (refer to the instructions for the assignment) is only partially achieved. The writer has described the materials necessary to complete the activity (i.e., 1.5v C or D battery, thin copper wire, an iron nail, some adhesive tape, small nail brads, a sheet of paper, and a small ruler). The writer has provided a limited application of subject matter knowledge as he or she has not explicitly stated what variables affect the strength of the electromagnet. The writer has described an experimental design for testing the implied variables; however, the response does not state how the data from the investigation will be recorded and analyzed. Lastly, the writer has identified one basic physical science concept (i.e., behavior of electrical current in a wire); however, the prompt asks the writer to identify two basic physical science concepts. Overall, this response reflects a limited, poorly reasoned understanding of the topic.
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.