Massachusetts Comprehensive Assessment System

2019, High School Intro Physics

Question 44: Open-Response

Reporting Category: Heat and Heat Transfer
Standard: 3.2 - Explain how heat energy will move from a higher temperature to a lower temperature until equilibrium is reached.
Standard: Sci.HS.PHY.3.04 - Provide evidence that when two objects of different temperature are in thermal contact within a closed system, the transfer of thermal energy from higher-temperature objects to lower-temperature objects results in thermal equilibrium, or a more uniform energy distribution among the objects and that temperature changes necessary to achieve thermal equilibrium depend on the specific heat values of the two substances. Clarification Statement: Energy changes should be described both quantitatively in a single phase (Q = mcΔT) and conceptually either in a single phase or during a phase change.

A student heated 235 g of water in a beaker until the water reached 100°C. The student removed the beaker from the heat and placed the beaker on a counter in a 23°C room. The student recorded the temperature of the water every 4 minutes for 20 minutes. The data are shown in the table.

Time (min)	Water Temperature (°C)
0	100.0
4	86.1
8	77.8
12	70.6
16	65.6
20	61.7

Did heat flow from the air to the water or from the water to the air? Include data from the table to support your answer.
Identify the average temperature of the air in the room at 20 min.
Were the water and the air in thermal equilibrium at 20 min? Explain your answer.

The specific heat of water is $4.19 J / g \cdot ° C.$

Calculate the change in thermal energy of the water from 0 min to 20 min. Show your calculations and include units in your answer.

Scoring Guide for Idea Development

Select a score point in the table below to view the sample student response.

Score	Description
4	The response demonstrates a thorough understanding of thermal equilibrium, and the relationship among temperature changes in a substance, the amount of heat transferred, the mass of the substance, and the specific heat of the substance. The response correctly identifies the direction of heat flow between the air and water that is supported with data. The response correctly identifies the average temperature of the room at 20 minutes and clearly explains whether the water and air are at thermal equilibrium. The response also correctly calculates the change in thermal energy of the water.
4
3	The response demonstrates a general understanding of thermal equilibrium, and the relationship among temperature changes in a substance, the amount of heat transferred, the mass of the substance, and the specific heat of the substance.
2	The response demonstrates a limited understanding of thermal equilibrium, and the relationship among temperature changes in a substance, the amount of heat transferred, the mass of the substance, and the specific heat of the substance.
1	The response demonstrates a minimal understanding of thermal equilibrium, and the relationship among temperature changes in a substance, the amount of heat transferred, the mass of the substance, and the specific heat of the substance.
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 Intro Physics

Question 12: Waves and Radiation

Question 23: Motion and Forces

Question 32: Motion and Forces

Question 44: Heat and Heat Transfer

Question 45: Electromagnetism

Return to the MCAS 2019 Student Work Directory

Last Updated: May 5, 2020