Final answer:
When a spoon is placed in hot coffee, heat is transferred to the spoon from the coffee through conduction, raising the spoon's temperature and slightly cooling the coffee. For a hot/cold skinny white mocha, convection is used when steaming milk, and radiation would be used if reheating in a microwave.
Step-by-step explanation:
When a spoon at room temperature is placed in a cup of hot coffee, the process of conduction occurs. Conduction is the transfer of heat through direct contact. The metal spoon, which has a high thermal conductivity, quickly absorbs heat from the surrounding hot coffee. This heat transfer causes the temperature of the spoon to rise. The coffee's temperature slightly decreases as a result because energy is being transferred from the coffee to the spoon.
In the case of making a hot/cold skinny white mocha, these principles apply during preparation. Convection is involved when a barista steams milk, allowing the heat to circulate within the milk, ensuring the entire quantity of milk reaches a uniform temperature. If the beverage is a hot mocha, this steamed milk is then mixed with espresso and white chocolate flavoring. Conversely, for a cold mocha, the milk would not be steamed, or it would be steamed and then cooled down before being mixed with other ingredients. Lastly, if you were to reheat a cold mocha using a microwave, radiation would be the mode of heat transfer, as microwaves use electromagnetic waves to heat the liquid from within.