Ralph and Sheila are at a construction site and they are stacking bricks. The diagram above shows the bricks before they touch. Use the information in the diagram to answer the question.

Question

After the bricks have been touching for a while, whose top brick will be cooler?

Responses

a
Ralph’s top brick will be cooler than Sheila's top brick, because less energy has to transfer for Ralph’s brick’s molecules to reach the same temperature as the molecules of his bottom brick.
Ralph’s top brick will be cooler than Sheila's top brick, because less energy has to transfer for Ralph’s brick’s molecules to reach the same temperature as the molecules of his bottom brick.

b
Sheila's top brick will be cooler than Ralph’s top brick, because Sheila’s started with more total energy, so less energy had to transfer for both her bricks to reach the same total energy.
Sheila's top brick will be cooler than Ralph’s top brick, because Sheila’s started with more total energy, so less energy had to transfer for both her bricks to reach the same total energy.

c
Sheila’s top brick will be cooler than Ralph’s top brick, because the energy that transferred to Sheila’s was spread out over more molecules.

Answer 1

To determine whose top brick will be cooler after a period of energy transfer, we need to consider how heat transfer affects the temperature of the bricks.

The key points to consider:

1. If both bricks are initially at different temperatures and they come into contact, heat will flow from the warmer brick to the cooler brick until they reach thermal equilibrium.
2. The rate and extent of heat transfer are influenced by the mass and material properties of the bricks, along with the initial temperature difference.

Examining the responses:

a) This suggests that Ralph’s top brick will be cooler due to less energy needing to transfer for thermal equilibrium. This could be valid if Ralph's top brick started at a significantly lower temperature compared to Sheila's.

b) This implies Sheila's top brick will be cooler because she started with more total energy. This isn't quite accurate; even if Sheila's brick started with more energy, that wouldn't necessarily make it cooler—we look at the final equilibrium temperatures instead.

c) This suggests that Sheila’s top brick will be cooler because the energy transferred to it was spread over more molecules. This reasoning is sound in thermodynamics as it reflects how heat energy is distributed among different masses and can affect temperature.

Given these considerations, option (c) is the most reasonable conclusion. Sheila's top brick could be cooler because energy transfer to it may result in a lower temperature due to this distribution over more molecules.

Therefore, the best choice is:

c Sheila’s top brick will be cooler than Ralph’s top brick, because the energy that transferred to Sheila’s was spread out over more molecules.