Which statement best describes convection in a house?

• A. Heat transferred by the movement of a fluid between areas of differing temperatures
• B. Heat transferred by direct contact
• C. Heat transfer by radiation from a hot surface
• D. Heat generated within a material

Answer: (A)

Convection is heat transfer by the movement of a fluid, such as air, carrying thermal energy from warmer areas to cooler areas. In a house, air that’s heated by a furnace or radiator becomes lighter and rises toward the ceiling, while cooler air moves in to replace it at lower levels, creating a circulating current. This natural flow—often amplified by fans or vents if present—distributes heat throughout rooms without direct contact between surfaces.

This differs from conduction, which is heat transfer through direct contact of solids; and from radiation, which is heat transfer from a hot surface to surrounding space via electromagnetic waves. The idea of heat generated within a material refers to internal heat production, not transfer by moving air.