Question

3. In the thermos experiment, you made your own thermos and collected data comparing containers. Given what you have learned regarding heat transfer, which would stay the same temperature the longest in a thermos, hot or cold fluids? Defend your answer giving examples from the lesson and your experiment.

Answer 1

Both hot and cold fluids will maintain their temperature for a similar amount of time in a well-insulated thermos due to their efficiency in preventing heat transfer. This is backed by the principles of calorimetry and specific heat where materials with greater specific heat, like water, change temperature more slowly, further supported by experiments on heat transfer.

Step-by-step explanation:

In the thermos experiment, whether hot or cold fluids will stay the same temperature longer in a thermos can be inferred through an understanding of heat transfer principles. A thermos functions by minimizing heat transfer via conduction, convection, and radiation, allowing its contents to maintain temperature for extended periods. Both hot and cold fluids will lose or gain heat until they reach thermal equilibrium with their surroundings, yet due to the insulating properties of a thermos, this process is slowed down. In a well-insulated thermos, neither hot nor cold fluids have a significant advantage when it comes to maintaining their original temperature over time, as the efficiency of the thermos in preventing heat transfer is the determining factor.

From calorimetry, we've learned that the amount of heat lost or gained is contingent upon the mass of the substance and its specific heat. In calorimetry experiments like the one with the 500-mL and 2-L bottles of water, the 2-L bottle lost more heat because it contained a greater mass of water, even though both bottles reached the same final temperature. Similarly, a poorly insulated calorimeter would lead to greater apparent heat loss or gain in reactions or dissolutions because it allows more heat exchange with the surroundings.

Ideally, the materials with the greatest specific heat are those that would change temperature the most slowly when subjected to heat transfer, as seen in the example where water takes the longest to heat or cool. This characteristic makes it a common material for maintaining temperature in a calorimetric context or in insulating applications.