A scientist places a strip of hot metal on top of a block of another metal with a lower
melting point. The second metal quickly melts. What is the main type of heat transfer
responsible?

The heat transfer that we'll have will be:

- At first, the metal bar will emanate heat through radiation, to the atmosphere, and to the second metal, through conduction.

- Because of this, the second bar will start to increase it's temperature, up to the fusion point, spending the energy received on the fusion, and also radiating heat to the atmosphere. It won't emit heat in any other form, since heat transmission can happen only from a hot body to a cooler one, and the only things in contact are the two bars.