Why is heat flow considered predictable?

• A. It always moves from cold to hot temperature areas until equilibrium is reached.
• B. It always moves from high to low temperature areas until equilibrium is reached.
• C. It is governed by weather patterns.
• D. It occurs only in solids.

Answer: (B)

Heat flow is predictable because the driving force is a temperature difference: energy moves from hotter regions to cooler regions and continues until they share the same temperature. This direction comes from the tendency of natural processes to spread energy more evenly, leading to thermal equilibrium. So heat won’t spontaneously move from cold to hot unless external work is applied. Heat transfer can occur in solids, liquids, and gases (through conduction, convection) or even in empty space via radiation, but in all cases the flow follows from high to low temperature until balance is reached.