Can you see energy moving?
How Energy Moves Through the Atmosphere
Radiation is the transfer of energy by waves. Energy can travel as electromagnetic waves through air or empty space. The sun's energy travels through space by radiation. After sunlight heats the planet's surface, some heat radiates back into the atmosphere.
In conduction , heat is transferred from molecule to molecule by contact. Warmer molecules vibrate faster than cooler ones. They bump into the cooler molecules. When they do, they transfer some of their energy. Conduction happens mainly in the lower atmosphere. Can you explain why?
Convection is the transfer of heat by a current. Convection happens in a liquid or a gas. Air near the ground is warmed by heat radiating from Earth's surface. The warm air is less dense, so it rises. As it rises, it cools. The cool air is dense, so it sinks to the surface. This creates a convection current ( Figure below ). Convection is the most important way that heat travels in the atmosphere.
Convection currents are the main way that heat moves through the atmosphere. Why does warm air rise?
- conduction : Energy moves from higher temperature to lower temperature as heat. The material does not move, just the heat.
- convection : Movement of material due to differences in temperature.
- radiation : Movement of energy through the empty space between objects; this is by electromagnetic waves.
- In conduction, heat moves from areas of more heat to areas of less heat. The substances must be in direct contact.
- In convection, materials move depending on their heat relative to nearby materials.
- In radiation, energy moves by waves.
Use the resource below to answer the questions that follow.
- Conduction, Radiation, Convection at http://www.wisc-online.com/Objects/ViewObject.aspx?ID=sce304
- What is conduction?
- List three examples of good conductors.
- List three examples of poor conductors.
- What is radiation?
- List three examples of radiation.
- What is convection?
- List three examples of convection.
- What is moving in conduction?
- What is moving in convection?
- What is radiation?