An Experiment in Heat Transfer

Question

Students conducted a simple experiment to explore heat transfer. They constructed the closed system you see here: a metal soda can inside a styrofoam cup. The metal can was filled with 80°C water and placed into the styrofoam cup containing colder water, 10°C. The students predicted that the water in the metal can would decrease in temperature while the water temperature inside the cup would increase.
Question 1
PART A
One student in the group questioned the prediction. "How can heat energy move? There is nothing moving from the can to the cup!" How would you respond to this student?
Responses
A The student is correct. Since nothing is being transferred from one location to the other, the prediction is incorrect.The student is correct. Since nothing is being transferred from one location to the other, the prediction is incorrect.
B There is a change between the two containers. Heat from the hot water is being transferred to the water in styrofoam cup.There is a change between the two containers. Heat from the hot water is being transferred to the water in styrofoam cup.
C Heat moves easily out of the metal can because it is a conductor, but stops when it moves into the styrofoam cup, an insulator.Heat moves easily out of the metal can because it is a conductor, but stops when it moves into the styrofoam cup, an insulator.
D There is a change between the two containers. Kinetic energy from the hot water is being transferred to the water in styrofoam cup.There is a change between the two containers. Kinetic energy from the hot water is being transferred to the water in styrofoam cup.
Question 2

Heat Energy
Initial Temperature (°C) Final Temperature (°C)
Water in Metal Can 80 45
Water in Styrofoam Cup 10 45

PART B
Consider Part A. Based on the student data, the prediction was correct. Remember, heat is the transfer of energy from the high temperature object to the low temperature object until equilibrium is met and that was what happened in this case. How did this transfer of energy occur at the molecular level?
Responses
A Heat is transferred from one object to another object through particle collisions. The hot water had the greatest kinetic energy. Particle collisions transferred that energy from the hot water, to the can, and then to the cooler water.Heat is transferred from one object to another object through particle collisions. The hot water had the greatest kinetic energy. Particle collisions transferred that energy from the hot water, to the can, and then to the cooler water.
B Temperature changes due the transfer of heat energy. The hot water had the greatest heat energy. Heat was transferred from the inside of the can to the outside of the can, or into the water held in the styrofoam cup.Temperature changes due the transfer of heat energy. The hot water had the greatest heat energy. Heat was transferred from the inside of the can to the outside of the can, or into the water held in the styrofoam cup.
C Heat energy always travels from high to low. The heat energy flowed through the water in the can, through the metal since it is a good conductor, and then out into the cooler water, raising the temperature there.Heat energy always travels from high to low. The heat energy flowed through the water in the can, through the metal since it is a good conductor, and then out into the cooler water, raising the temperature there.
D Because the hot water had the highest temperature, it also had the greatest stored or potential energy. That energy was shared with the cooler water until the two volumes were at the same temperature.

Answer 1

Question 1 - Part A:
To respond to the student's question regarding heat transfer, the best answer is:

B There is a change between the two containers. Heat from the hot water is being transferred to the water in the styrofoam cup.

This response explains that while it may seem like nothing is moving physically, heat energy is indeed being transferred from the warmer water to the cooler water through conduction across the metal can.

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Question 2 - Part B:
For the explanation of how the transfer of energy occurred at the molecular level, the most appropriate response is:

A Heat is transferred from one object to another object through particle collisions. The hot water had the greatest kinetic energy. Particle collisions transferred that energy from the hot water, to the can, and then to the cooler water.

This answer accurately describes the mechanism of heat transfer at the molecular level through collisions between particles, leading to energy exchange between the hot and cool substances until thermal equilibrium is reached.