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Massachusetts Comprehensive Assessment System
2014, High School Technology/Engineering
 Question 45: Open-Response |
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Reporting Category: Fluid and Thermal Systems
Standard: 3.1 - Explain the basic differences between open fluid systems (e.g., irrigation, forced hot air system, air compressors) and closed fluid systems (e.g., forced hot water system, hydraulic brakes).
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The diagram below represents an evaporative cooling system for a house, which is suitable for use in hot, arid climates. When the fans are on, hot outside air is pulled over a water reservoir. The resulting cool, moist air is then blown into the house through the duct system.
- Identify the two fluids used in the evaporative cooling system.
- Identify whether the evaporative cooling system is an open system or a closed system. Explain your answer.
- Describe one change in the evaporative cooling system that would allow more cool air to be produced.
In this system, some heat is transferred by conduction between the air and the water.- Describe how conduction occurs between the air and the water.
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Scoring Guide and Sample Student Work
Select a score point in the table below to view the sample student response.
| Score | Description |
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| 4 |
The response demonstrates a thorough understanding of heat transfer and the differences between open and closed fluid systems. The response correctly identifies the two fluids used in the evaporative cooling system and identifies and explains why the evaporative cooling system is an open system. The response also correctly describes one change in the evaporative cooling system that would allow more cool air to be produced and describes how conduction occurs between the air and the water. |
| 4 |
| 3 |
The response demonstrates a general understanding of heat transfer and the differences between open and closed fluid systems. |
| 2 |
The response demonstrates a limited understanding of heat transfer and the differences between open and closed fluid systems. |
| 1 |
The response demonstrates a minimal understanding of heat transfer and the differences between open and closed fluid systems. |
| 0 |
The response is incorrect or contains some correct work that is irrelevant to the skill or concept being measured. |
Note: There are 2 sample student responses for Score Point 4.
High School Technology/Engineering
- Question 11: Construction and Manufacturing
- Question 23: Engineering Design
- Question 33: Electrical and Communication Systems
- Question 44: Electrical and Communication Systems
- Question 45: Fluid and Thermal Systems
Return to the MCAS 2014 Student Work Directory
Last Updated: August 5, 2013
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