Convection is the transfer of heat through the movement of a fluid (such as air or water). This process occurs when a warmer, less dense fluid rises, and a cooler, denser fluid sinks, creating a continuous circulation of the fluid.
How does convection work?
Convection occurs in fluids because as the fluid is heated, its particles gain energy and move faster, causing the fluid to expand and become less dense. This less dense, warmer fluid then rises, while the cooler, denser fluid sinks. This cycle creates a convection current, which transfers heat from one place to another.
Examples of convection
Boiling water: The heat from the bottom of the pot causes the water at the bottom to become less dense and rise. As it reaches the top, it cools and becomes denser, then sinks back down to be reheated.
Atmospheric convection: The sun heats the Earth's surface, causing the air above it to warm and rise. As the warm air rises, it cools and forms clouds, eventually releasing the heat as it sinks back down.
From Molecules to Organisms: Structures and Processes
Students who demonstrate understanding can:
Develop models to describe that organisms have unique and diverse life cycles but all have in common birth, growth, reproduction, and death.
Biological Evolution: Unity and Diversity
Students who demonstrate understanding can:
Use evidence to construct an explanation for how the variations in characteristics among individuals of the same species may provide advantages in surviving, finding mates, and reproducing.