This document describes an experiment that tested the effectiveness of aluminum foil and plastic wrap at prolonging the temperature of hot water. Two trays of hot water were covered, one with aluminum foil and one with plastic wrap, and their temperatures were measured over 30 minutes. The results showed that the water covered with aluminum foil maintained a higher temperature, at 37°C, compared to the water covered with plastic wrap, which cooled to 30°C. Therefore, the conclusion is that aluminum foil more effectively prolongs the temperature of a substance by minimizing heat transfer compared to plastic wrap.