Which best explains why water boils in a pot sitting over fire?

When a pot of water is placed over a fire, the thermal energy generated by the flames is transferred to the pot, which subsequently heats the water inside. This process occurs through conduction, where the heat from the fire directly raises the temperature of the pot and then the water. As the water absorbs this thermal energy, its temperature increases until it reaches the boiling point. At this point, the water transitions from a liquid state to a gaseous state, manifesting as steam.

The correct answer highlights the direct relationship between the heat source (the fire) and the water, emphasizing that thermal energy from the fire moves to the water, which is essential for the boiling process to occur. This understanding is crucial in recognizing the mechanism of heat transfer in cooking and in various other thermal processes.