Study Guide

Field 108: Earth Science 
Sample Constructed-Response Assignment

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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. However, your final response to the assignment must be either:

  1. typed into the on-screen response box,
  2. written on a response sheet and scanned using the scanner provided at your workstation, or
  3. 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.

Instructions for scanning your response sheet(s) are available by clicking the "Scanning Help" button at the top of the screen.

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.

PURPOSE: the extent to which the response achieves the purpose of the assignment
SUBJECT KNOWLEDGE: appropriateness and accuracy in the application of subject knowledge
SUPPORT: quality and relevance of supporting evidence
RATIONALE: soundness of argument and degree of understanding of the subject area

The 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. You may not use any reference materials during the test. 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 NOT be scored.

Sample Constructed-Response Assignment

Use the information in the exhibits to complete the assignment that follows.

Analyze the information provided in the exhibits and, citing specific evidence from the exhibits, write a response of approximately 300 to 600 words in which you:

Class Context

In an earth science class, students will be applying their previous knowledge of density to its relationship with temperature and plate tectonic motion. This lab activity is performed as a demonstration due to possible fire hazards. The demonstration is set up, as shown in the lesson plan. Students are allowed to come up to the demonstration by pairs to make observations and then finish the lab reports at their desks. This demonstration is set up to continuously run for the entire class period to allow for further observations and discussions. Students are familiar with writing laboratory reports and analyzing and presenting data.

Excerpt from Lesson Plan

The following is an excerpt from a high school earth science class's lesson plan.

Unit Subject: Earth Systems

Subject of the Lesson: Thermal Convection

Student Content Standard:

HS-ESS2-31 Develop a model based on evidence of Earth's interior to describe the cycling of matter by thermal convection.

Lesson Objective:

  • Students will be able to explain how matter is cycled in the asthenosphere by thermal convection, using observational evidence from a dynamic model of paired convection cells.

Materials:

  • 13 point 5 by 23 point 0 by 7 point 0 centimeters glass pan
  • Hot plate
  • Vegetable oil
  • Parsley flakes
  • Bricks

Setup:

A set-up is shown of a glass baking pan resting on two bricks

It's placed in such a way as to support the ends of the pan. There is a hot plate that has been turned on beneath the middle of the pan and in between the bricks. It is not touching the pan. Inside the pan is vegetable oil with parsley flakes suspended evenly throughout the oil.

Assessment:

Students will be assessed based on their explanation of how matter is cycled in the demonstration and apply the concept to the asthenosphere, using observational evidence.

 

Sample of Student Work

Lab Assignment with Student Work

Directions: Write an explanation on how matter is cycled in the asthenosphere, using observational evidence from the demonstration.

The cycling of matter in the asthenosphere is a rapid circulation of particles driven by heat. This rapid cycling occurs because the asthenosphere is in a liquid state. As the heat source heats the matter, particles start to move faster and become less dense. This is because more collisions occur, which moves the particles further apart. Then as matter rises, it starts to cool and collisions become fewer as density increases. As the particles sink, they come closer to the heat source, and the cycle begins again. This cyclic pattern is known as the convection currents. I have observed these convection currents during the demonstration. The parsley flakes showed the path of two convection cells that had developed in the vegetable oil, moving in a circular pattern. The current did not happen until the heat source was turned on to heat the middle of the pan and did not stop until the hot plate was turned off at the end of class.

Sample Strong Response to the Constructed-Response Assignment

This student shows a strong understanding of density by giving a detailed description of the mechanism by which molecules react to changing temperature and the corresponding change in density. Since density equals mass divided by volume, as temperature goes up and the particles move apart with increased collisions there indeed would be a smaller mass/volume ratio. Conversely, as temperature goes down the particles have fewer collisions and move closer together, the mass/volume ratio increases.

The significant need in the given student response is a better understanding of the physical properties of the asthenosphere. The student describes the asthenosphere as liquid and that it undergoes "a rapid circulation." This is not the case. The asthenosphere is only partially melted (4% liquid) and should be considered to behave as a solid, although due to higher temperatures and pressures it is a solid that is mobile. It is the higher pressure that keeps the rock from melting completely. Given that the asthenosphere is mostly solid it will move much slower than the oil in the experiment.

In order to help this student improve their understanding of the physical properties of the asthenosphere and understand the difference between convection in solids and the convection in the experiment there needs to be further instruction. I would have students brainstorm examples of solids that are soft and malleable so they can have a more realistic picture in their minds of a solid that is mobile. They may come up with peanut butter, toothpaste, or mayonnaise, or even aluminum foil or gold. Now that they can understand there are solids that flow or change shape, they need to think about how a harder and denser solid would be able to flow, too.

With increasing temperature and pressure even solids flow over time and the class could experiment with wood that bends when weight is applied or have plastic begin to deform as we apply heat. Another example to show the class is old glass that deformed and has become wavy. The age of the glass can also help students understand that these processes occur slowly. (Although we must realize that geologic time scales are much slower than even that!)

Since this student's lack of understanding is probably not unique, for future instruction I would want to add the activity on the physical properties of the asthenosphere described above. I would also emphasize how experiments are simplifications used to highlight a specific process but the real world is much more complex. Part of the experimental procedure is then to evaluate how the experiment is both similar and different from real world conditions. For this specific experiment I would ask the students how the asthenosphere is not like the oil. Hopefully, this would make students think about the differences in physical properties between the asthenosphere and the oil, and the conditions that cause the asthenosphere to move much more slowly than the oil.

This experiment could also be modified with some pieces of material that float representing the lithospheric plates. Students could observe how the plates spread apart from the area of high heat and the speed of the plates could be measured. They may even be able to observe the experiment with different viscosities of liquids to show how the different materials move the plates at different speeds. In all cases the students need to compare the experimental values to real plate speeds to show the limitations of the experiment.

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 by responding generally to all aspects of the prompt (refer to the instructions for the assignment). The answer to the first bullet clearly identifies a significant strength and weakness. These two items are then described and supported with additional evidence. This shows the depth of knowledge in the response. For example, the equation for density is stated and shown to support the student's response so it was correct. The weakness cited is an inaccuracy in the analogy relating the experiment to the real asthenosphere. Accurate information about the asthenosphere is provided to highlight the inaccuracy, and specific details provide support. For example, the response states that the asthenosphere is not liquid but should be considered a solid that is mobile. The examinee supports this by specifically and accurately stating that the asthenosphere is only partially melted, with 4 percent liquid.

The second bullet is largely achieved by the inclusion of several ideas about how to address the weakness. These ideas are thoroughly described and are a sequence of steps demonstrating a reasoned understanding of the subject matter as well as an understanding of teaching. Brainstorming and additional experimentation are used to address the lack of understanding of the physical properties of the asthenosphere.

The third bullet response states that the analysis that has been done in the first and second bullets can be used in the future. With the detailed descriptions in the second bullet we might consider that this bullet has been achieved. This response, however, goes on to also suggest changes to the experiment. The additional question about how the oil and the asthenosphere are different may help the student understand the difference between the experiment and the asthenosphere better. By running the experiment with different materials, the student will be developing better analytical skills, and the simulated lithospheric plates will help lead the student to the next topic within plate tectonics: the motion of the plates. All of these show a depth of knowledge and a reasoned understanding both of the topic and of teaching.

Overall, the response provides a general understanding of the subject matter.

Sample Weak Response to the Constructed-Response Assignment

A significant strength is that the student understands the relationship between temperature and density, and the student can describe it in detail. A significant weakness is that they don't understand that after the material rises in a convection cell it then moves away from the heat source before it sinks back down and then moves over the heat source to rise again. This creates a circular pattern. The student only says that the material heats up and rises, then it cools and sinks back down.

To help the student understand this circulation pattern I would have them draw the pattern that they observe.

For future instruction, I would have the students trace the circular pattern of the parsley. I would also put something that floats on top of the oil. These would be like plates. The students will see how the plates move apart from the heat source because the oil (asthenosphere) drags them along. Then when the students see the tectonic maps and learn about divergent and convergent plate boundaries they will understand the motion of the asthenosphere and how it makes the plates move.

One other thing to note is that all experiments in the class involve the use of safety equipment. Even though the students are coming up to observe the experiment and not running it at their own lab tables, they should have close-toed shoes, lab coats, and goggles on to keep them safe.

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 first bullet is only partially achieved. The response correctly identifies the significant strength in the student's work. The weakness cited, however, is not significant. The student does not provide a detailed description of a convection cell but uses the terms "cyclic pattern" and "circulation" enough to indicate understanding of the concept. The weakness that should be identified is that the asthenosphere is not liquid and does not move quickly like the oil does in the experiment.

The second bullet is based on the incorrect weakness identified in the first bullet, which is a problem since there is still a major misunderstanding that is not being addressed. In addition, the answer shows no depth or support, and merely identifies the instructional strategy rather than describes it.

The third bullet does meet the idea of purpose and begins to show a reasoned understanding of the topic. However, the addition of the information about lab safety is not critical to this prompt.

Overall the purpose is partially achieved, there is limited application of relevant subject matter knowledge and support, and there is only a limited understanding of the critical issues in this prompt.

Performance Characteristics

The following characteristics guide the scoring of responses to the constructed-response assignment.

Characteristics that guide the scoring of responses
Purpose The extent to which the response achieves the purpose of the assignment
Subject Matter Knowledge The accuracy and appropriateness in the application of subject matter knowledge
Support The quality and relevance of supporting details
Rationale The soundness of argument and degree of understanding of the subject matter

Scoring Scale

Scores will be assigned to each response to the constructed-response assignment according to the following scoring scale.

Score Scale with description for each score point.
Score Point Score Point Description
4  start bold The "4" response reflects a thorough knowledge and understanding of the subject matter. end bold 
  • The purpose of the assignment is fully achieved.
  • There is a substantial, accurate, and appropriate application of subject matter knowledge.
  • The supporting evidence is sound; there are high-quality, relevant examples.
  • The response reflects an ably reasoned, comprehensive understanding of the topic.
3  start bold The "3" response reflects a general knowledge and understanding of the subject matter. end bold 
  • The purpose of the assignment is largely achieved.
  • There is a generally accurate and appropriate application of subject matter knowledge.
  • The supporting evidence generally supports the discussion; there are some relevant examples.
  • The response reflects a general understanding of the topic.
2  start bold The "2" response reflects a partial knowledge and understanding of the subject matter. end bold 
  • The purpose of the assignment is partially achieved.
  • There is a limited, possibly inaccurate or inappropriate application of subject matter knowledge.
  • The supporting evidence is limited; there are few relevant examples.
  • The response reflects a limited, poorly reasoned understanding of the topic.
1  start bold The "1" response reflects little or no knowledge and understanding of the subject matter. end bold 
  • The purpose of the assignment is not achieved.
  • There is little or no appropriate or accurate application of subject matter knowledge.
  • The supporting evidence, if present, is weak; there are few or no relevant examples.
  • The response reflects little or no reasoning about or understanding of the topic.
U The response is unscorable because it is illegible, not written to the assigned topic, written in a language other than English, or lacking a sufficient amount of original work to score.
B There is no response to the assignment.

Acknowledgments

1Republished with permission of The National Academies Press, from Next Generation Science Standards: for states, by states - HS-ESS2-3 Standards; permission conveyed through Copyright Clearance Center, Inc.