Amp Up Your Energy Knowledge: NCEA Level 1 Practice Test 2026!

Convection is heat transfer carried by moving fluids. When a fluid is heated, it becomes less dense and tends to rise, while cooler fluid sinks, creating circulating loops. This movement of the fluid itself transports heat from warmer regions to cooler ones, which is why systems with circulating water or air heat more efficiently. Conduction involves heat transfer through direct contact in solids (or stationary fluids) without bulk fluid motion, radiation transfers heat by waves through space, and evaporation is a phase-change process, not a mode defined by moving fluid carrying heat. So the description of fluids moving heat in loops points to convection.