The circulation of material through differences caused by temperature is known as what?

• A. Convection
• B. Erosion
• C. Conduction
• D. Radiation

Answer: (A)

Convection is the circulation of material caused by temperature differences. When a fluid is heated, it becomes lighter and rises; as it cools, it becomes denser and sinks, creating a looping motion that moves both material and heat. This process happens in the atmosphere, oceans, and Earth's mantle, driving weather patterns, ocean currents, and large-scale mantle flow. Conduction, by contrast, is heat transfer through direct contact without bulk movement, radiation is heat transfer by waves through space or transparent media, and erosion is the removal of material, not a circulation of material due to heat. So the circulating movement driven by temperature differences is convection.