Final answer:
Energy is redistributed between a hot coffee and a room temperature spoon through conduction, resulting in the spoon warming up and the coffee cooling down until thermal equilibrium is reached.
Step-by-step explanation:
Heat Transfer in Coffee
When a spoon at room temperature is placed into a cup of hot coffee, energy redistribution occurs through a process known as conduction. This is the transfer of heat via direct contact, resulting in the spoon absorbing heat from the hot coffee. Consequently, the spoon's temperature increases while the coffee's temperature decreases until both reach thermal equilibrium. This demonstrates the principle that heat flows spontaneously from a hotter object to a colder one, leading to a more uniform distribution of thermal energy.
Additionally, when discussing the insulation properties of a thermos, it's relevant to note that such containers are designed to prevent heat transfer through conduction, convection, and radiation. A thermos full of coffee retains its temperature partly because of the vacuum between its double walls, significantly reducing heat loss via conduction and convection, while reflective surfaces limit radiative heat loss.
In another scenario, if you pour coffee into an unlidded cup and intend to drink it after a short period, adding cream right before you drink it will result in a slightly hotter coffee. This is due to the fact that the coffee cools at a slower rate when the cream, which has its own temperature, is not added immediately.