Question

unit exam: thermal energy and earths processes
a group of students is investigating the transfer of thermal energy. they place a heated metal block at 100°c into a closed, insulated container filled with water at 20°c. the students measured the temperatures of the water and metal block every minute for 10 minutes.
which result would best demonstrate the second law of thermodynamics in this experiment?
the water decreases to a lower temperature while the metal block stays at 100°c
the metal block continues to heat the water, but their temperatures never equatize
the metal block stays at 100°c and the water stays at 20°c throughout the experiment
the water and the metal block both change temperatures until they reach 60°c

Explanation:

The second - law of thermodynamics states that heat will flow from a higher - temperature object to a lower - temperature object until thermal equilibrium is reached. In this experiment, the heated metal block at 100°C (higher temperature) and water at 20°C (lower temperature) will exchange heat. The water and the metal block will change temperatures until they reach the same final temperature, which is an example of heat transfer towards thermal equilibrium as described by the second - law of thermodynamics.

Answer:

The water and the metal block both change temperatures until they reach 60°C (assuming no heat loss to the surroundings and equal heat capacities for simplicity, although the actual final temperature depends on specific heat capacities and masses; the key is that they reach thermal equilibrium).