Which method is least likely to enhance the rate of heat transfer?

Using substances with higher specific heats is the least likely method to enhance the rate of heat transfer in a convection scenario. Specific heat is the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. While substances with higher specific heat can store more heat without a significant change in temperature, they do not necessarily facilitate quicker heat transfer.

In convection, heat transfer is dependent on the temperature difference between the fluid (such as air or water) and the surface it is in contact with, as well as the movement of the fluid itself. The other methods listed directly influence the efficiency and rate at which heat is transferred. For instance, increasing the area of contact allows more surface area for heat exchange, while decreasing the distance between objects can quickly facilitate energy transfer due to reduced thermal resistance. Additionally, increasing the time of contact can allow more heat to flow from one body to another.

In contrast, focusing solely on using substances with higher specific heats does not inherently improve the rate at which heat energy is exchanged between the two bodies involved, making this choice the least effective method for enhancing heat transfer.