Final answer:
Two cups are used in a coffee cup calorimeter setup to provide extra insulation, aiming to minimize heat loss to the surroundings and improve the accuracy of calorimetry measurements, though they are less accurate than professional calorimeters.
Step-by-step explanation:
Two cups are used in a coffee cup calorimeter setup primarily to provide extra insulation. The nested Styrofoam cups create an insulated environment to help thermally isolate the system, which is usually a chemical reaction or solution, from the external surroundings. The insulation helps to minimize the heat exchange with the outside environment, allowing for more accurate measurements of the heat involved in chemical processes.
However, it's worth noting that while this setup provides some insulation, these simple calorimeters do allow more heat exchange than more sophisticated calorimeters. Therefore, while extra insulation is the primary purpose, this simple calorimeter design cannot entirely prevent heat loss to the surroundings and is less accurate compared to professional-grade equipment. Yet, they are easily accessible and suitable for educational purposes in demonstrating how calorimetry works.